归并排序

来源：互联网发布：array_push 二元数组编辑：程序博客网时间：2024/06/04 00:49

#include <stdio.h>#include <string.h>#include <stdlib.h>void merge(int * array, int start, int middle, int end){int nIter=0;int nIter1=start;//a[start]...a[middle]int nIter2=middle+1;//a[middle+1]...a[end]int * tempArray=new int[end-start+1];memset(tempArray, 0, (end-start+1)*sizeof(int));while(nIter1 <= middle && nIter2 <= end)       //访问到其中一段结束为止，另一段剩余部分则直接复制{if(array[nIter1]<=array[nIter2]){tempArray[nIter]=array[nIter1];nIter1++;}else{tempArray[nIter]=array[nIter2];nIter2++;}nIter++;}for(;nIter1<=middle;nIter1++, nIter++)tempArray[nIter]=array[nIter1];for(;nIter2<=end;nIter2++, nIter++)tempArray[nIter]=array[nIter2];int i=0;for(; start+i<=end; i++)array[start+i]=tempArray[i];}void merge_sort(int array[], int start, int end){if(start==end)return; int middle=(end+start)/2; merge_sort(array, start, middle);merge_sort(array, middle+1, end);merge(array, start, middle, end);}void print_array(int array[], int n){int nIter=0;for(; nIter<n; nIter++){printf("%d", array[nIter]);}printf("\n");}void main(){int array[]={0,30,155,1,80,300,170,40,99};printf("before sort:\n");print_array(array, 9);merge_sort(array, 0, 8);printf("after sort:\n");print_array(array, 9);}

归并排序所用的时间复杂度为：nlgn

空间复杂度为：n

编程时，注意技巧性的东西：将两个已排序的数组进行合并；