归并排序

代码如下：

#include <stdio.h>#include <stdlib.h>#include <time.h>#define N 50000void merge(int [],int,int,int);//归并排序数组合并函数声明void mergesort(int [],int,int);//归并排序数组排序函数声明//主函数int  main(){    int i,a1[N];    double t1,t2,t3,t4;            for(i=0;i<N;i++)    {        a1[i]=rand()%N;    }        //归并排序N个随机数字所用的时间    t2=clock();    mergesort(a1,0,N-1);    t2=clock()-t2;        /*排好序的结果*/    for(i=0;i<N-1;i++)    {         printf("%4d\n",a1[i]);    }    printf("\n归并排序%d个随机数字所用时间为:%f毫秒\n",N,(double)t2);    getch();    return 1;}//归并排序//归并排序合并数组函数的具体实现void merge(int a[],int low,int middle,int high){    int h,i,j,k;    int b[N];    h=low;    i=low;    j=middle+1;    while(h<=middle&&j<=high)    {        if(a[h]<=a[j])        {            b[i]=a[h];            h++;        }        else        {             b[i]=a[j];            j++;        }        i++;    }    if(h>middle)    for(k=j;k<=high;k++)    {        b[i]=a[k];        i++;     }    else    {        for(k=h;k<=middle;k++)        {             b[i]=a[k];            i++;        }    }    for(k=low;k<=high;k++)    {        a[k]=b[k];    }}//归并排序函数的具体实现void mergesort(int a[],int low,int high){    int middle;    if(low<high)    {        middle=(low+high)/2;        mergesort(a,low,middle);        mergesort(a,middle+1,high);        merge(a,low,middle,high);    }}

 

完。