# 在矩陣中查找唯一元素 > 原文： [https://www.geeksforgeeks.org/find-unique-elements-matrix/](https://www.geeksforgeeks.org/find-unique-elements-matrix/) 給定具有 n 行和 m 列的矩陣 mat [] []。 我們需要在矩陣中找到唯一元素，即矩陣中未重復的元素或頻率為 1 的元素。 **示例**： ``` Input : 20 15 30 2 2 3 5 30 6 7 6 8 Output : 3 20 5 7 8 15 Input : 1 2 3 5 6 2 1 3 5 6 2 2 Output : No unique element in the matrix ``` 請按照以下步驟查找唯一元素： 1.創建一個空的哈希表或字典。 2.遍歷矩陣的所有元素 3.如果字典中存在元素，則增加其計數 4.否則插入值為= 1 的元素。 ## C++ ```cpp // C++ program to find unique // element in matrix #include<bits/stdc++.h> using namespace std; #define R 4 #define C 4 // function that calculate unique element int unique(int mat[R][C], int n, int m) { ????int maximum = 0, flag = 0; ????for(int i = 0; i < n; i++)? ????????for(int j = 0; j < m; j++) ????????????// Find maximum element in ????????????// a matrix ????????????if(maximum < mat[i][j]) ????????????????????maximum = mat[i][j]; ????// Take 1-D array of (maximum + 1) ????// size ????int b[maximum + 1] = {0}; ????for(int i = 0 ; i < n; i++) ????????for(int j = 0; j < m; j++) ????????????b[mat[i][j]]++; ????//print unique element ????for(int i = 1; i <= maximum; i++) ????????if(b[i] == 1) ????????????cout << i << " "; ????????????flag = 1; ????if(!flag){ ????????cout << "No unique element in the matrix"; ????} } // Driver program int main() { ????int mat[R][C] = {{ 1, 2, 3, 20}, ?????????????????????{5, 6, 20, 25}, ?????????????????????{1, 3, 5, 6}, ?????????????????????{6, 7, 8, 15}}; ????// function that calculate unique element ????unique(mat, R, C); ????return 0; } // This code is contributed by Naman_Garg. ``` ## Java ```java // Java program to find unique // element in matrix class GFG { static int R = 4, C = 4; // function that calculate? // unique element static void unique(int mat[][],? ???????????????????int n, int m) { ????int maximum = 0, flag = 0; ????for(int i = 0; i < n; i++)? ????????for(int j = 0; j < m; j++) ????????????// Find maximum element? ????????????// in a matrix ????????????if(maximum < mat[i][j]) ????????????????????maximum = mat[i][j]; ????// Take 1-D array of? ????// (maximum + 1) size ????int b[] = new int [maximum + 1]; ????for(int i = 0 ; i < n; i++) ????????for(int j = 0; j < m; j++) ????????????b[mat[i][j]]++; ????//print unique element ????for(int i = 1; i <= maximum; i++) ????????if(b[i] == 1) ????????????System.out.print(i + " "); ????????????flag = 1; ????if(flag == 0) ????{ ????????System.out.println("No unique element " +? ????????????????????????????????"in the matrix"); ????} } // Driver Code public static void main(String args[]) { ????int mat[][] = {{1, 2, 3, 20}, ???????????????????{5, 6, 20, 25}, ???????????????????{1, 3, 5, 6}, ???????????????????{6, 7, 8, 15}}; ????// function that calculate? ????// unique element ????unique(mat, R, C); } } // This code is contributed // by Arnab Kundu ``` ## Python3 ```py # Python 3 program to find unique # element in matrix def unique(mat, n, m): ????maximum = 0; flag = 0 ????for i in range(0, n): ????????for j in range(0, m): ????????????# Find maximum element in ????????????# a matrix ????????????if(maximum < mat[i][j]): ????????????????maximum = mat[i][j]; ????uniqueElementDict = [0] * (maximum + 1) ????# loops to traverse through the matrix? ????for i in range(0, n): ????????for j in range(0, m): ????????????????uniqueElementDict[mat[i][j]] += 1 ????# Print all those keys whose count is 1 ????for key in range(maximum + 1): ????????if uniqueElementDict[key] == 1: ????????????print (key, end = " ") ????????????flag = 1 ????if(flag == 0): ????????print("No unique element in the matrix") # Driver Code mat = [[1, 2, 3, 20],? ???????[5, 6, 20, 25], ???????[1, 3, 5, 6], ???????[6, 7, 8, 15]] n = 4 m = 4 unique(mat, n, m) ``` ## C# ```cs // C# program to find unique? // element in matrix using System; class GFG? {? static int R = 4, C = 4;? // function that calculate? // unique element? static void unique(int [,]mat,? ???????????????????int n, int m)? {? ????int maximum = 0, flag = 0;? ????for(int i = 0; i < n; i++)? ????????for(int j = 0; j < m; j++)? ????????????// Find maximum element? ????????????// in a matrix? ????????????if(maximum < mat[i, j])? ????????????????????maximum = mat[i, j];? ????// Take 1-D array of? ????// (maximum + 1) size? ????int []b = new int [maximum + 1];? ????for(int i = 0 ; i < n; i++)? ????????for(int j = 0; j < m; j++)? ????????????b[mat[i, j]]++;? ????// print unique element? ????for(int i = 1; i <= maximum; i++)? ????????if(b[i] == 1)? ????????????Console.Write(i + " ");? ????????????flag = 1;? ????if(flag == 0)? ????{? ????????Console.WriteLine("No unique element " +? ???????????????????????????????"in the matrix");? ????}? }? // Driver Code? public static void Main()? {? ????int [,]mat = {{1, 2, 3, 20},? ??????????????????{5, 6, 20, 25},? ??????????????????{1, 3, 5, 6},? ??????????????????{6, 7, 8, 15}};? ????// function that calculate? ????// unique element? ????unique(mat, R, C);? }? }? // This code is contributed? // by Subhadeep ``` ## PHP ```php <?php // PHP program to find unique // element in matrix $R = 4; $C = 4; // function that calculate unique element function unique($mat, $n, $m) { ????$maximum = 0; ????$flag = 0; ????for($i = 0; $i < $n; $i++)? ????????for($j = 0; $j < $m; $j++) ????????????// Find maximum element in ????????????// a matrix ????????????if($maximum < $mat[$i][$j]) ????????????????????$maximum = $mat[$i][$j]; ????// Take 1-D array of (maximum + 1) ????// size ????$b = array(); ????for($j = 0; $j < $maximum + 1; $j++) ????????$b[$j] = 0; ????for($i = 0 ; $i < $n; $i++) ????????for($j = 0; $j < $m; $j++) ????????????$b[$mat[$i][$j]]++; ????// print unique element ????for($i = 1; $i <= $maximum; $i++) ????????if($b[$i] == 1) ????????????echo "$i "; ????????????$flag = 1; ????if(!$flag) ????{ ????????echo "No unique element in the matrix"; ????} } // Driver Code $mat = array(array(1, 2, 3, 20), ?????????????array(5, 6, 20, 25), ?????????????array(1, 3, 5, 6), ?????????????array(6, 7, 8, 15)); // function that calculate unique element unique($mat, $R, $C); // This code is contributed by iAyushRaj ?> ``` **輸出**： ``` 2 7 8 25 15 ``` * * * * * *