归并排序C++

#include <iostream>using namespace std;/* *把数组从中间分为2部分，分别将两部分排好序后，调用merge将2个有序序列合并成1个有序序列 * */void merge(int* arr, int start, int mid, int end){int* p = new int[1000];int* q = new int[1000];for(int i = start; i <= mid; i++){p[i] = arr[i];}for(int j = mid + 1; j <= end; j++){q[j] = arr[j];}int i = start, j = mid + 1;int pos = start;while(i <= mid || j <= end){if(i > mid){ //处理一方到达尽头arr[pos++] = q[j++];continue;}if(j > end){arr[pos++] = p[i++];continue;}if(p[i] <= q[j]){arr[pos++] = p[i++];}else if(p[i] > q[j]){arr[pos++] = q[j++];}}delete[] p;delete[] q;}void merge_sort(int* arr, int start, int end){if(start >= end) return; //递归出口int mid = start + (end - start) / 2;merge_sort(arr, start, mid);merge_sort(arr, mid + 1, end);merge(arr, start, mid, end);}int main(){int arr[] = { 3, 5, 6 ,8, 2, 1, 9, 4, 0, 7};merge_sort(arr, 0, 9);for(int i = 0; i < 10; i++){cout << arr[i] << " ";}system("PAUSE");}