# 將大小為 n 的數組合并為大小為 m + n 的另一個數組 > 原文： [https://www.geeksforgeeks.org/merge-one-array-of-size-n-into-another-one-of-size-mn/](https://www.geeksforgeeks.org/merge-one-array-of-size-n-into-another-one-of-size-mn/) 有兩個排序的數組。 第一個大小為 m + n，僅包含 m 個元素。 另一個大小為 n，包含 n 個元素。 將這兩個數組合并到大小為 m + n 的第一個數組中，以便對輸出進行排序。 輸入：具有 m + n 個元素的數組（mPlusN []）。  NA = >數組 mPlusN []中的值未填充/不可用。 應該有 n 個這樣的數組塊。 輸入：具有 n 個元素的數組（N []）。  輸出：N []合并為 mPlusN []（已修改的 mPlusN []）  **算法**： ``` Let first array be mPlusN[] and other array be N[] 1) Move m elements of mPlusN[] to end. 2) Start from nth element of mPlusN[] and 0th element of N[] and merge them into mPlusN[]. ``` 下面是上述算法的實現： ## C++ ```cpp // C++ program to Merge an array of? // size n into another array of size m + n #include <bits/stdc++.h> using namespace std; /* Assuming -1 is filled for the places ???where element is not available */ #define NA -1 /* Function to move m elements at? ???the end of array mPlusN[] */ void moveToEnd(int mPlusN[], int size) { ???int j = size - 1; ???for (int i = size - 1; i >= 0; i--) ?????if (mPlusN[i] != NA) ?????{ ????????mPlusN[j] = mPlusN[i]; ????????j--; ?????} } /* Merges array N[] of size n into ???array mPlusN[] of size m+n*/ int merge(int mPlusN[], int N[], int m, int n) { ???int i = n; /* Current index of i/p part of mPlusN[]*/ ???int j = 0; /* Current index of N[]*/ ???int k = 0; /* Current index of output mPlusN[]*/ ???while (k < (m + n)) ???{ ????/* Take an element from mPlusN[] if ????a) value of the picked element is smaller? ???????and we have not reached end of it ????b) We have reached end of N[] */ ????if ((i < (m + n) && mPlusN[i] <= N[j]) || (j == n)) ????{ ????????mPlusN[k] = mPlusN[i]; ????????k++; ????????i++; ????} ????else // Otherwise take element from N[] ????{ ???????mPlusN[k] = N[j]; ???????k++; ???????j++; ????} ???} } /* Utility that prints out an array on a line */ void printArray(int arr[], int size) { ???for (int i = 0; i < size; i++) ???cout << arr[i] << " "; ???cout << endl; } /* Driver function to test above functions */ int main() { ???/* Initialize arrays */ ???int mPlusN[] = {2, 8, NA, NA, NA, 13, NA, 15, 20}; ???int N[] = {5, 7, 9, 25}; ???int n = sizeof(N) / sizeof(N[0]); ???int m = sizeof(mPlusN) / sizeof(mPlusN[0]) - n; ???/*Move the m elements at the end of mPlusN*/ ???moveToEnd(mPlusN, m + n); ???/*Merge N[] into mPlusN[] */ ???merge(mPlusN, N, m, n); ???/* Print the resultant mPlusN */ ???printArray(mPlusN, m+n); ???return 0; } ```