归并排序

利用分治法和递归思想实现归并排序

#include<iostream>using namespace std;void MergeArray(int arr[], int first, int mid, int last, int temp[]){int i = first, j = mid + 1;int k = 0;while (i <= mid && j <= last){if (arr[i]<arr[j]){temp[k++] = arr[i++];}else{temp[k++] = arr[j++];}}while (i <= mid){temp[k++] = arr[i++];}while (j <= last){temp[k++] = arr[j++];}for (i = 0; i<k; i++){arr[first + i] = temp[i]; }}void Merge(int arr[], int left, int right, int temp[]){if (left >= right)return;else{int mid = (left + right) / 2;Merge(arr, left, mid, temp);Merge(arr, mid + 1, right, temp);MergeArray(arr, left, mid, right, temp);}}void mergeSort(int arr[], int len){int *temp = new int[len];Merge(arr, 0, len - 1, temp);memcpy(arr, temp, sizeof(int)*len);delete[]temp;}int main(){int arr[] = { 1,2,4,5,6,3,7,8};mergeSort(arr, sizeof(arr) / sizeof(int));for (int i = 0; i < sizeof(arr) / sizeof(arr[0]); i++)cout<<arr[i]<<" ";cout << endl;return 0;}