归并排序

归并排序是将数组元素分成左右两个部分，对两边分别进行归并排序：把分开后的两部分再各自分成两部分，进行归并排序.....分到不能再分为止

以下为代码演示

#include <stdio.h>void printA(int *a,int len){int i;for(i = 0; i < len; i++){printf("%4d",a[i]);}printf("\n");}//合并两个顺序表void merge(int *a, int left, int mid, int right, int *tmp){int i = left;int j = mid+1;int k = 0;while(i <= mid && j <= right){if(a[i] > a[j])tmp[k++] = a[j++];elsetmp[k++] = a[i++];}while(i <= mid)tmp[k++] = a[i++];while(j <= right)tmp[k++] = a[j++];k = 0;for(i = left; i <= right; i++){a[i] = tmp[k++];}}void mergeSort(int *a, int left, int right, int *tmp){if(left >= right)return;int mid = (left+right)/2;mergeSort(a, left, mid, tmp);  //对左边部分归并排序mergeSort(a,mid+1,right,tmp);  //对右边部分归并排序merge(a,left,mid,right,tmp);   //将两边数据进行归并}int main(){int a[10] = {7,2,9,4,1,3,8,6,5,0};int len = sizeof(a)/sizeof(a[0]);int tmp[10];mergeSort(a,0,len-1,tmp);printA(a,len);return 0;}