归并排序的实现_by watson.long

归并排序的实现_by watson.long

————————————————————————————

#include "stdio.h"

void mergesort(int a[],int r[],int left,int right);
void merge(int a[],int b[],int left,int mid,int right);

void main(int argc,char *argv[])
{
    int data[10]={9,1,2,4,6,10,23,5,3,56};
    int result[10]={0};
    int i=0;
    /*merge sort*/
    mergesort(data,result,0,9);
    return;
}


/*merge sort*/
void mergesort(int a[],int r[],int left,int right)
{
    int mid;
    if(left<right)
    {
        mid=(left+right)/2;
        mergesort(a,r,left,mid);
        mergesort(a,r,mid+1,right);
        merge(a,r,left,mid,right);
    }
}

void merge(int a[],int b[],int left,int mid,int right)
{
    int k;
    int s1,s2;
    int i=left;

    for(k=left;k<=right;k++) b[k]=a[k];

    s1=left;
    s2=mid+1;

    while(s1<=mid&&s2<=right)
    {
        if(b[s1]<b[s2]) a[i++]=b[s1++];
        else a[i++]=b[s2++];
    }

    while(s1<=mid) a[i++]=b[s1++];
    while(s2<=right) a[i++]=b[s2++];

    return;
}