## 十、Python編程計算24點（之二） ----From a high school student's view to learnPython 關鍵字： python 高中生學編程 Python編程入門 計算24點表達式計算 組合問題 三、程序實現 說完了該列舉的問題，接下來就是程序的書寫部分了，現在我們要回憶之前學的一系列知識，包括函數，列表，循環等等。首先我們來解決組合的書寫問題，因為有四個數，我們便可以把這四個數歸到同一個列表中，然后再通過調用來運用，但是在這里我們需要創造兩個列表，一個是函數里的列表，另一個是函數外引入的參數，因為是要寫組合，所以我們就應該將引入的參數分別的賦值給我們在函數內新建的列表，然后再在之后的程序中使用已被賦值的列表。 <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p><p><span>5</span></p></td><td valign="top"><p><span>?<wbr> ?<wbr>a=[</wbr></wbr></span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>]</span></p><p><span>?<wbr> ?<wbr/></wbr></span><span>for</span> <span>i1</span> <span>in</span><span>range(</span><span>3</span><span>):</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>0</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>1</span><span>];a[</span><span>2</span><span>]=c[</span><span>2</span><span>];a[</span><span>3</span><span>]=c[</span><span>3</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>1</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>2</span><span>];a[</span><span>2</span><span>]=c[</span><span>1</span><span>];a[</span><span>3</span><span>]=c[</span><span>3</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>2</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>3</span><span>];a[</span><span>2</span><span>]=c[</span><span>1</span><span>];a[</span><span>3</span><span>]=c[</span><span>2</span><span>]</span></p></td></tr></tbody></table> a就是我們新建的列表，其實列表里的元素隨便是什么都可以，只要有四個，因為會被替換掉，接下來就需要用一個循環來解決組合問題。由于有三種情況，所以我們可以用一個三個條件的循環，分別是(ab)(cd) ，(ac) (bd) ，(ad) (bc) 然后再對range函數進行for語句循環操作。這里要注意的一點是：range中是從0開始計算，而且結尾應是前一個數，所以是以3結尾。這樣我們就成功的寫出了循環的組合語句，我們就不用再在之后的程序中浪費時間重復操作了。 四選三的組合語句也差不多，如下 <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p><p><span>5</span></p><p><span>6</span></p><p><span>7</span></p></td><td valign="top"><p><span>?<wbr> ?<wbr>a=[</wbr></wbr></span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>]</span></p><p><span>?<wbr> ?<wbr>sign=[</wbr></wbr></span><span><i>'+'</i></span><span>,</span><span><i>'-'</i></span><span>]</span></p><p><span>?<wbr> ?<wbr/></wbr></span><span>for</span> <span>i1</span> <span>in</span><span>range(</span><span>4</span><span>):</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>0</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>1</span><span>];a[</span><span>2</span><span>]=c[</span><span>2</span><span>];a[</span><span>3</span><span>]=c[</span><span>3</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>1</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>1</span><span>];a[</span><span>2</span><span>]=c[</span><span>3</span><span>];a[</span><span>3</span><span>]=c[</span><span>2</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>2</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>2</span><span>];a[</span><span>2</span><span>]=c[</span><span>3</span><span>];a[</span><span>3</span><span>]=c[</span><span>1</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>3</span><span>:a[</span><span>0</span><span>]=c[</span><span>1</span><span>];a[</span><span>1</span><span>]=c[</span><span>2</span><span>];a[</span><span>2</span><span>]=c[</span><span>3</span><span>];a[</span><span>3</span><span>]=c[</span><span>0</span><span>]</span></p></td></tr></tbody></table> 接下來我們就要進行枚舉各種情況了，但是在枚舉前，我們應該再思考一下到底有什么地方可以在進行簡化。仔細觀察前面列的所有情況，我們可以發現含有+-這兩個符號的式子很多，有些式子甚至含有兩對到三對，但是如果我們一一去列舉所有的情況，未免太復雜：+++，++-，+--，+-+，-++，-+-，--+，---一共八種，也就是說我們要為了之一種簡單的情況寫八遍差不多的代碼，那我們為什么不做一個甚至多重的for循環呢？ <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p></td><td valign="top"><p><span>?<wbr> ?<wbr>sign=[</wbr></wbr></span><span><i>'+'</i></span><span>,</span><span><i>'-'</i></span><span>]</span></p><p><span>?<wbr> ?<wbr> for</wbr></wbr></span><span>i2</span> <span>in</span> <span>sign:</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr/></wbr></wbr></wbr></wbr></wbr></span><span>for</span> <span>i3</span> <span>in</span><span>sign:</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr/></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span> <span>for</span><span>i4</span> <span>in</span> <span>sign:</span></p></td></tr></tbody></table> 首先建立一個列表（line1）然后再做一個三重循環，當然這里的循環次數和式子中+-的個數要保持一致。但是為什么*/不用for循環來做呢，因為我們發現其實(c*/d) <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p><p><span>5</span></p><p><span>6</span></p><p><span>7</span></p><p><span>8</span></p><p><span>9</span></p><p><span>10</span></p><p><span>11</span></p><p><span>12</span></p><p><span>13</span></p><p><span>14</span></p><p><span>15</span></p><p><span>16</span></p><p><span>17</span></p></td><td valign="top"><p><span>?<wbr> ?<wbr>num4list=[]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr>a=[</wbr></wbr></span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>]</span></p><p><span>?<wbr> ?<wbr/></wbr></span><span>for</span> <span>i1</span> <span>in</span><span>range(</span><span>3</span><span>):</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>0</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>1</span><span>];a[</span><span>2</span><span>]=c[</span><span>2</span><span>];a[</span><span>3</span><span>]=c[</span><span>3</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>1</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>2</span><span>];a[</span><span>2</span><span>]=c[</span><span>1</span><span>];a[</span><span>3</span><span>]=c[</span><span>3</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>2</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>3</span><span>];a[</span><span>2</span><span>]=c[</span><span>1</span><span>];a[</span><span>3</span><span>]=c[</span><span>2</span><span>]</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(</wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'/'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>')'</i></span><span>)</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(</wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'/'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>')'</i></span><span>)</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(</wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'/'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>')'</i></span><span>)</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(</wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'/'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>')'</i></span><span>)</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(</wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'/'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>')'</i></span><span>)</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(</wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'/'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>')'</i></span><span>)</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(</wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'*'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>')'</i></span><span>)</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(</wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'*'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>')'</i></span><span>)</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(</wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'*'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>')'</i></span><span>)</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(</wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'*'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>')'</i></span><span>)</span></p></td></tr></tbody></table> 看起來很復雜，其實找到規律之后就十分容易了，由于/的符號有順序一說（a/b和b/a的不同）所以我們需要調換順序，然后依照規律，我們就可以列出一共10種不同的情況。要注意的是，如果不是str()函數，則需要用雙引號來表示字符串的意義。 <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p><p><span>5</span></p><p><span>6</span></p><p><span>7</span></p><p><span>8</span></p><p><span>9</span></p><p><span>10</span></p><p><span>11</span></p><p><span>12</span></p><p><span>13</span></p><p><span>14</span></p><p><span>15</span></p></td><td valign="top"><p><span>?<wbr> ?<wbr> ?<wbr>num4list.append(str(a[</wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>2</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>1</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>1</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>2</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>1</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>2</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>2</span><span>]))</span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>1</span><span>]))</span></p><p><span>?<wbr/></span><span>?<wbr>?<wbr> ?<wbr>num4list.append(str(a[</wbr></wbr></wbr></span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>0</span><span>]))</span></p></td></tr></tbody></table> 這種情況就是a*/b+-c*/d，由于ab和cd之間都有除號，所以這兩個字母都需要調換順序，而且因為中間的符號有減號，所以我們還需要將前兩個數字和后兩個數字調換順序來滿足所有的情況。而由于只里面只有一個+-所以并不需要用循環來簡化，只需枚舉即可。 <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p><p><span>5</span></p><p><span>6</span></p><p><span>7</span></p><p><span>8</span></p><p><span>9</span></p><p><span>10</span></p><p><span>11</span></p><p><span>12</span></p><p><span>13</span></p><p><span>14</span></p><p><span>15</span></p><p><span>16</span></p></td><td valign="top"><p><span>?<wbr> ?<wbr>num3list=[]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr>sign=[</wbr></wbr></span><span><i>'+'</i></span><span>,</span><span><i>'-'</i></span><span>]</span></p><p><span>?<wbr> ?<wbr>a=[</wbr></wbr></span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>]</span></p><p><span>?<wbr> ?<wbr/></wbr></span><span>for</span> <span>i1</span> <span>in</span><span>range(</span><span>3</span><span>):</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>0</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>1</span><span>];a[</span><span>2</span><span>]=c[</span><span>2</span><span>];a[</span><span>3</span><span>]=c[</span><span>3</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>1</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>2</span><span>];a[</span><span>2</span><span>]=c[</span><span>1</span><span>];a[</span><span>3</span><span>]=c[</span><span>3</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>2</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>3</span><span>];a[</span><span>2</span><span>]=c[</span><span>1</span><span>];a[</span><span>3</span><span>]=c[</span><span>2</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>for</span> <span>i2</span><span>in</span> <span>sign:</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr/></wbr></wbr></wbr></wbr></wbr></span><span>for</span> <span>i3</span> <span>in</span><span>sign:</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr/></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span> <span>for</span><span>i4</span> <span>in</span> <span>sign:</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span> <span>if</span><span>i2==</span><span><i>'+'</i></span><span>:</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>i2=</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><span><i>''</i></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num3list.append(i2+</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>0</span><span>])+i3+str(a[</span><span>1</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'*'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>2</span><span>])+i4+str(a[</span><span>3</span><span>])+</span><span><i>')'</i></span><span>)</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num3list.append(i2+</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>0</span><span>])+i3+str(a[</span><span>1</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'/'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>2</span><span>])+i4+str(a[</span><span>3</span><span>])+</span><span><i>')'</i></span><span>)</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num3list.append(i2+</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+str(a[</span><span>2</span><span>])+i3+str(a[</span><span>3</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'/'</i></span><span>+</span><span><i>'('</i></span><span>+str(a[</span><span>0</span><span>])+i4+str(a[</span><span>1</span><span>])+</span><span><i>')'</i></span><span>)</span></p></td></tr></tbody></table> 這是(a+-b)*/(c+-d)的情況，要注意的是，在這幾行代碼中我們用到了一個三重循環，而+-只有兩種，原因是我們在括號的最前面又加了一個符號，仔細觀察，我們可以發現這個符號是對第一個括號內的正負進行的判定，因為在第一個括號內會出現a與b調換的情況，而且我們發現第一個括號內會出現答案是負數的情況，但是不要忘了，在第二個括號內的情況和第一個括號內的情況是完全相同的，所以第二個括號內也會出現負數的情況，當第一和第二個括號內的結果均為負數時，就又變成了正數（中間是*/），所以我們并不用在每個括號前加一個符號，取而代之的是在整個式子之前加正負號就可以了。 <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p><p><span>5</span></p><p><span>6</span></p><p><span>7</span></p><p><span>8</span></p><p><span>9</span></p><p><span>10</span></p><p><span>11</span></p><p><span>12</span></p><p><span>13</span></p><p><span>14</span></p><p><span>15</span></p><p><span>16</span></p><p><span>17</span></p></td><td valign="top"><p><span>?<wbr> ?<wbr>num4list=[]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr>a=[99,99,99,99]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr> for i1 inrange(3):</wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==0:a[0]=c[0];a[1]=c[1];a[2]=c[2];a[3]=c[3]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==1:a[0]=c[0];a[1]=c[2];a[2]=c[1];a[3]=c[3]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==2:a[0]=c[0];a[1]=c[3];a[2]=c[1];a[3]=c[2]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr>?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append('('+str(a[0])+'*'+str(a[1])+')'+'/'+'('+str(a[2])+'*'+str(a[3])+')')</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append('('+str(a[2])+'*'+str(a[3])+')'+'/'+'('+str(a[0])+'*'+str(a[1])+')')</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append('('+str(a[2])+'*'+str(a[3])+')'+'/'+'('+str(a[0])+'/'+str(a[1])+')')</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append('('+str(a[2])+'*'+str(a[3])+')'+'/'+'('+str(a[1])+'/'+str(a[0])+')')</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append('('+str(a[0])+'*'+str(a[1])+')'+'/'+'('+str(a[2])+'/'+str(a[3])+')')</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append('('+str(a[0])+'*'+str(a[1])+')'+'/'+'('+str(a[3])+'/'+str(a[2])+')')</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append('('+str(a[0])+'*'+str(a[1])+')'+'*'+'('+str(a[2])+'/'+str(a[3])+')')</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append('('+str(a[0])+'*'+str(a[1])+')'+'*'+'('+str(a[3])+'/'+str(a[2])+')')</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append('('+str(a[2])+'*'+str(a[3])+')'+'*'+'('+str(a[0])+'/'+str(a[1])+')')</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append('('+str(a[2])+'*'+str(a[3])+')'+'*'+'('+str(a[1])+'/'+str(a[0])+')')</wbr></wbr></wbr></wbr></span></p></td></tr></tbody></table> 這是(a*/b)*/(c*/d)的情況，大家如果觀察可以發現第一個括號內并沒有/的情況，這是因為如果第一個括號內的符號是/，兩個括號中間的符號必須是*，否則答案不可能是24，但是如果中間的符號是*，就沒必要考慮兩個括號的擺放順序的問題了，所以我索性讓第一個括號的符號均為*，看起來也比較整齊。其它的步驟還是和前幾個差不多，調換/兩端元素的位置，找到規律之后十分簡單。 <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p><p><span>5</span></p><p><span>6</span></p><p><span>7</span></p><p><span>8</span></p><p><span>9</span></p><p><span>10</span></p><p><span>11</span></p><p><span>12</span></p><p><span>13</span></p><p><span>14</span></p><p><span>15</span></p></td><td valign="top"><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>2</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>1</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>1</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>2</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>1</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'+'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>2</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>2</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>0</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>1</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr>num4list.append(str(a[</wbr></wbr></wbr></wbr></span><span>2</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'-'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>0</span><span>]))</span></p></td></tr></tbody></table> 這種情況就是a*/b+-c*/d，由于也是兩個數字一組的情況，之前的組合代碼和上一種情況相同，所以我就索性將兩種情況合并在一起，節省了很多時間，但是要注意的是這種情況包含兩個*/和一個+-，所以情況比較多，但是/-/的情況顯然不可能所以排除，大家要注意不要遺漏或者重復。 接下來就是三個一組的情況： <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p><p><span>5</span></p><p><span>6</span></p><p><span>7</span></p><p><span>8</span></p><p><span>9</span></p><p><span>10</span></p><p><span>11</span></p><p><span>12</span></p><p><span>13</span></p><p><span>14</span></p><p><span>15</span></p><p><br/></p></td><td valign="top"><p><span>?<wbr> ?<wbr>num5list=[]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr>a=[</wbr></wbr></span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>]</span></p><p><span>?<wbr> ?<wbr>sign=[</wbr></wbr></span><span><i>'+'</i></span><span>,</span><span><i>'-'</i></span><span>]</span></p><p><span>?<wbr> ?<wbr/></wbr></span><span>for</span> <span>i1</span> <span>in</span><span>range(</span><span>4</span><span>):</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>0</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>1</span><span>];a[</span><span>2</span><span>]=c[</span><span>2</span><span>];a[</span><span>3</span><span>]=c[</span><span>3</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>1</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>1</span><span>];a[</span><span>2</span><span>]=c[</span><span>3</span><span>];a[</span><span>3</span><span>]=c[</span><span>2</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>2</span><span>:a[</span><span>0</span><span>]=c[</span><span>0</span><span>];a[</span><span>1</span><span>]=c[</span><span>2</span><span>];a[</span><span>2</span><span>]=c[</span><span>3</span><span>];a[</span><span>3</span><span>]=c[</span><span>1</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>if</span><span>i1==</span><span>3</span><span>:a[</span><span>0</span><span>]=c[</span><span>1</span><span>];a[</span><span>1</span><span>]=c[</span><span>2</span><span>];a[</span><span>2</span><span>]=c[</span><span>3</span><span>];a[</span><span>3</span><span>]=c[</span><span>0</span><span>]</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></span> <span>for</span> <span>i2</span><span>in</span> <span>sign:</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr/></wbr></wbr></wbr></wbr></wbr></span><span>for</span> <span>i3</span> <span>in</span><span>sign:</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr/></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span> <span>for</span><span>i4</span> <span>in</span> <span>sign:</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr/></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span> <span>if</span><span>i2==</span><span><i>'+'</i></span><span>:</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>i2=</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><span><i>''</i></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num5list.append(</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+i2+str(a[</span><span>0</span><span>])+i3+str(a[</span><span>1</span><span>])+i4+str(a[</span><span>2</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num5list.append(</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span><span><i>'('</i></span><span>+i2+str(a[</span><span>0</span><span>])+i3+str(a[</span><span>1</span><span>])+i4+str(a[</span><span>2</span><span>])+</span><span><i>')'</i></span><span>+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p></td></tr></tbody></table> (a+-b+-c)*/d由于是三個一組的情況，之前在組合問題中說過有四種情況，而且由于前兩個符號都是+-，而我又在第一個數字前加了一個符號來避免調換順序，我們可以用一個三重循環來解決重復書寫的問題，和之前介紹過的技巧一樣。同樣大家也要注意第一個符號是+的情況是無意義的，所以要把它去掉（line12-line13）。 <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p><p><span>5</span></p><p><span>6</span></p><p><span>7</span></p><p><span>8</span></p><p><span>9</span></p><p><span>10</span></p><p><span>11</span></p><p><span>12</span></p><p><span>13</span></p><p><span>14</span></p><p><span>15</span></p><p><span>16</span></p><p><span>17</span></p><p><span>18</span></p><p><span>19</span></p><p><span>20</span></p><p><span>21</span></p><p><span>22</span></p><p><span>23</span></p><p><span>24</span></p><p><span>25</span></p><p><span>26</span></p><p><span>27</span></p><p><span>28</span></p><p><span>29</span></p><p><span>30</span></p><p><span>31</span></p><p><span>32</span></p><p><span>33</span></p><p><span>34</span></p><p><span>35</span></p><p><span>36</span></p><p><span>37</span></p><p><span>38</span></p><p><span>39</span></p><p><span>40</span></p><p><span>41</span></p><p><span>42</span></p><p><span>43</span></p><p><span>44</span></p></td><td valign="top"><p><span>?<wbr> ?<wbr>num6list=[]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr>a=[99,99,99,99]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr>sign=['+','-']</wbr></wbr></span></p><p><span>?<wbr> ?<wbr> for i1 inrange(4):</wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==0: a[0]=c[0]; a[1]=c[1]; a[2]=c[2];a[3]=c[3]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==1: a[0]=c[0]; a[1]=c[1]; a[2]=c[3];a[3]=c[2]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==2: a[0]=c[0]; a[1]=c[2]; a[2]=c[3];a[3]=c[1]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==3: a[0]=c[1]; a[1]=c[2]; a[2]=c[3];a[3]=c[0]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> for i2 in sign:</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>num6list.append(str(a[0])+'*'+str(a[1])+'*'+str(a[2])+i2+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>num6list.append(str(a[0])+'*'+str(a[1])+'/'+str(a[2])+i2+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>num6list.append(str(a[0])+'*'+str(a[2])+'/'+str(a[1])+i2+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>num6list.append(str(a[2])+'*'+str(a[1])+'/'+str(a[0])+i2+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr> for i3 insign:</wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> if i2=='-' and i3=='-':</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>continue</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> if i3=='+':</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>i3=''</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[0])+i2+str(a[1])+'*'+str(a[2])+')'+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[0])+i2+str(a[1])+'/'+str(a[2])+')'+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[0])+i2+str(a[2])+'/'+str(a[1])+')'+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[0])+i2+str(a[1])+'*'+str(a[2])+')'+'/'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[0])+i2+str(a[1])+'/'+str(a[2])+')'+'/'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[0])+i2+str(a[2])+'/'+str(a[1])+')'+'/'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[1])+i2+str(a[0])+'*'+str(a[2])+')'+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[1])+i2+str(a[0])+'/'+str(a[2])+')'+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[1])+i2+str(a[2])+'/'+str(a[0])+')'+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[1])+i2+str(a[0])+'*'+str(a[2])+')'+'/'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[1])+i2+str(a[0])+'/'+str(a[2])+')'+'/'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[1])+i2+str(a[2])+'/'+str(a[0])+')'+'/'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[2])+i2+str(a[1])+'*'+str(a[0])+')'+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[2])+i2+str(a[1])+'/'+str(a[0])+')'+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[2])+i2+str(a[0])+'/'+str(a[1])+')'+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[2])+i2+str(a[1])+'*'+str(a[0])+')'+'/'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[2])+i2+str(a[1])+'/'+str(a[0])+')'+'/'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append('('+i3+str(a[2])+i2+str(a[0])+'/'+str(a[1])+')'+'/'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append(i3+str(a[3])+'/'+'('+str(a[0])+i2+str(a[1])+'*'+str(a[2])+')')</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append(i3+str(a[3])+'/'+'('+str(a[0])+i2+str(a[2])+'/'+str(a[1])+')')</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append(i3+str(a[3])+'/'+'('+str(a[0])+i2+str(a[1])+'/'+str(a[2])+')')</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append(i3+str(a[3])+'/'+'('+str(a[1])+i2+str(a[0])+'*'+str(a[2])+')')</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append(i3+str(a[3])+'/'+'('+str(a[1])+i2+str(a[0])+'/'+str(a[2])+')')</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append(i3+str(a[3])+'/'+'('+str(a[1])+i2+str(a[2])+'/'+str(a[0])+')')</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append(i3+str(a[3])+'/'+'('+str(a[2])+i2+str(a[1])+'*'+str(a[0])+')')</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append(i3+str(a[3])+'/'+'('+str(a[2])+i2+str(a[1])+'/'+str(a[0])+')')</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr>num6list.append(i3+str(a[3])+'/'+'('+str(a[2])+i2+str(a[0])+'/'+str(a[1])+')')</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p></td></tr></tbody></table> 接下來這個是a*/b*/c+-d和(a+-b*/c)*/d的兩種情況的合并，由于這兩種都是三個一組的情況，合并可以少些很多重復的代碼，但是要注意的是，這兩種情況并不是在最后合并，它們各自的前提條件的代碼有所區別。因為第一個式子中只有一個+-，而第二個式子中有兩個（式子最前要加一個符號），所以所進行的循環操作的次數是不一樣的，但是我們仍然可以把它們合并在一起，只需在第一個循環操作結束后直接輸出第一個式子的結果，把它們加入到列表中，然后再進行下兩個循環操作就可以了。但是對于第二個式子，我們要注意的是在括號之后的符號有/，所以就不可避免的要調換位置，但是再調換位置之后會出現代碼不整齊的情況，影響美觀，所以我們不妨把這一類單分出來放在最下面。 <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p><p><span>5</span></p><p><span>6</span></p><p><span>7</span></p><p><span>8</span></p><p><span>9</span></p><p><span>10</span></p></td><td valign="top"><p><span>?<wbr> ?<wbr>num7list=[]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr>a=[</wbr></wbr></span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>,</span><span>99</span><span>]</span></p><p><span>?<wbr> ?<wbr>a[</wbr></wbr></span><span>0</span><span>]=c[</span><span>0</span><span>]</span></p><p><span>?<wbr> ?<wbr>a[</wbr></wbr></span><span>1</span><span>]=c[</span><span>1</span><span>]</span></p><p><span>?<wbr> ?<wbr>a[</wbr></wbr></span><span>2</span><span>]=c[</span><span>2</span><span>]</span></p><p><span>?<wbr> ?<wbr>a[</wbr></wbr></span><span>3</span><span>]=c[</span><span>3</span><span>]</span></p><p><span>?<wbr> ?<wbr>num7list.append(str(a[</wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>3</span><span>]))</span></p><p><span>?<wbr> ?<wbr>num7list.append(str(a[</wbr></wbr></span><span>3</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>0</span><span>]))</span></p><p><span>?<wbr> ?<wbr>num7list.append(str(a[</wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>2</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>1</span><span>]))</span></p><p><span>?<wbr> ?<wbr>num7list.append(str(a[</wbr></wbr></span><span>0</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>1</span><span>])+</span><span><i>'*'</i></span><span>+str(a[</span><span>3</span><span>])+</span><span><i>'/'</i></span><span>+str(a[</span><span>2</span><span>]))</span></p></td></tr></tbody></table> 這種就是a*/b*/c*/d的情況，但是由于一乘兩除或者三個除號的情況是不可能形成24的，所以我們這里只考慮兩乘一除的情況，由于沒有+-，我們就不需要組合的代碼，只需將c列表中的元素賦值給a列表中的每個元素即可。 <table cellspacing="0" cellpadding="0"><tbody><tr><td valign="top"><p><span>1</span></p><p><span>2</span></p><p><span>3</span></p><p><span>4</span></p><p><span>5</span></p><p><span>6</span></p><p><span>7</span></p><p><span>8</span></p><p><span>9</span></p><p><span>10</span></p><p><span>11</span></p><p><span>12</span></p><p><span>13</span></p><p><span>14</span></p><p><span>15</span></p><p><span>16</span></p><p><span>17</span></p><p><span>18</span></p><p><span>19</span></p><p><span>20</span></p><p><span>21</span></p><p><span>22</span></p><p><span>23</span></p><p><span>24</span></p><p><span>25</span></p><p><span>26</span></p><p><span>27</span></p><p><span>28</span></p><p><span>29</span></p><p><span>30</span></p><p><span>31</span></p><p><span>32</span></p><p><span>33</span></p><p><span>34</span></p><p><span>35</span></p><p><span>36</span></p><p><span>37</span></p><p><span>38</span></p><p><span>39</span></p><p><span>40</span></p><p><span>41</span></p><p><span>42</span></p><p><span>43</span></p><p><span>44</span></p><p><span>45</span></p><p><span>46</span></p><p><span>47</span></p></td><td valign="top"><p><span>?<wbr> ?<wbr>num8list=[]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr>a=[99,99,99,99]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr>sign=['+','-']</wbr></wbr></span></p><p><span>?<wbr> ?<wbr> for i1 inrange(6):</wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==0:a[0]=c[0];a[1]=c[1];a[2]=c[2];a[3]=c[3]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==1:a[0]=c[0];a[1]=c[2];a[2]=c[1];a[3]=c[3]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==2:a[0]=c[0];a[1]=c[3];a[2]=c[1];a[3]=c[2]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==3:a[0]=c[2];a[1]=c[3];a[2]=c[0];a[3]=c[1]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==4:a[0]=c[1];a[1]=c[3];a[2]=c[0];a[3]=c[2]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==5:a[0]=c[1];a[1]=c[2];a[2]=c[0];a[3]=c[3]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> for i2 in sign:</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr> for i3 insign:</wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> if i2=='-' andi3=='-':</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> continue</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> if i2=='+':</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> i2=''</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num8list.append('('+i2+str(a[0])+i3+str(a[1])+')'+'*'+str(a[2])+'+'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num8list.append('('+i2+str(a[0])+i3+str(a[1])+')'+'*'+str(a[3])+'+'+str(a[2]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num8list.append('('+i2+str(a[0])+i3+str(a[1])+')'+'*'+str(a[2])+'-'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num8list.append('('+i2+str(a[0])+i3+str(a[1])+')'+'*'+str(a[3])+'-'+str(a[2]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num8list.append('('+i2+str(a[0])+i3+str(a[1])+')'+'/'+str(a[2])+'+'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num8list.append('('+i2+str(a[0])+i3+str(a[1])+')'+'/'+str(a[3])+'+'+str(a[2]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num8list.append('('+i2+str(a[0])+i3+str(a[1])+')'+'/'+str(a[2])+'-'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num8list.append('('+i2+str(a[0])+i3+str(a[1])+')'+'/'+str(a[3])+'-'+str(a[2]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><br/></p><p><span>?<wbr> ?<wbr>num10list=[]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr>a=[99,99,99,99]</wbr></wbr></span></p><p><span>?<wbr> ?<wbr>sign=['+','-']</wbr></wbr></span></p><p><span>?<wbr> ?<wbr> for i1 inrange(6):</wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==0:a[0]=c[0];a[1]=c[1];a[2]=c[2];a[3]=c[3]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==1:a[0]=c[0];a[1]=c[2];a[2]=c[1];a[3]=c[3]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==2:a[0]=c[0];a[1]=c[3];a[2]=c[1];a[3]=c[2]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==3:a[0]=c[2];a[1]=c[3];a[2]=c[0];a[3]=c[1]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==4:a[0]=c[1];a[1]=c[3];a[2]=c[0];a[3]=c[2]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> if i1==5:a[0]=c[1];a[1]=c[2];a[2]=c[0];a[3]=c[3]</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> for i2 in sign:</wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr> for i3 insign:</wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> if i2=='-' andi3=='-':</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> continue</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> if i2=='+':</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> i2=''</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num10list.append('('+i2+str(a[0])+i3+str(a[1])+')'+'*'+str(a[2])+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num10list.append('('+i2+str(a[0])+i3+str(a[1])+')'+'/'+str(a[2])+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num10list.append('('+i2+str(a[0])+i3+str(a[1])+')'+'*'+str(a[2])+'/'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num10list.append(str(a[2])+'/'+'('+i2+str(a[0])+i3+str(a[1])+')'+'*'+str(a[3]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><span>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr> ?<wbr>?<wbr> ?<wbr>num10list.append(str(a[3])+'/'+'('+i2+str(a[0])+i3+str(a[1])+')'+'*'+str(a[2]))</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></span></p><p><br/></p></td></tr></tbody></table> 接下來的這兩種情況就是最復雜的組合情況了，(a+-b)*/c+-d和(a+-b)*/c*/d這兩種情況下的組合，由于這兩種情況下用六種的組合情況可以少寫一些代碼，并且更加簡單，我們不妨把三種的組合代碼改為六種。? 到此為止，我們就把所有的組合的情況都列了出來，但是還有一些后續的程序來保證程序的運行和美觀。第一就是我們應該把每一種情況的代碼都寫入到一個函數中，這樣如果我們以后要用到的話，直接調用函數就能解決問題，第二就是我們還應該把所有的情況都加在一起，因為驗證的時候要用到的是所有的情況，而把它們合并到一個大函數中就不用一個一個調用了。 四、如何利用之前的函數來進行計算 由于我們的程序越做越大，如果我們還把所有的函數，代碼都放在一個模塊中，顯然是十分的復雜以及不方便，這時我們就要把代碼寫入不同的文件中，但是最后運行的時候，每個文件都需要被運行，那們我們怎么達成呢？這時我們就要用到import語句了，import語句的主要作用就是將多個文件引入到一個文件中，從而在運行一個文件時，其他的文件也能夠被運行。 import語句的語法： import 語句的模塊順序 我們推薦所有的模塊在 Python 模塊的開頭部分導入。而且好按照這樣的順序: Python 標準庫模塊? 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