归并排序总结

#include <bits/stdc++.h>
using namespace std;
int n,r[1000],r1[1000];
void merge_(int r[],int r1[],int low,int mid,int high)
{
    int i,j,k;
    i=low,j=mid+1,k=low;
    while((i<=mid)&&(j<=high))
        if(r[i]<=r[j])
            r1[k++]=r[i++];
        else r1[k++]=r[j++];
    while(i<=mid) r1[k++]=r[i++];
    while(j<=high) r1[k++]=r[j++];
}//合成
void mergepass(int r[],int r1[],int length)
{
    int i,j;
    i=0;
    while(i+2*length-1<n){
        merge_(r,r1,i,i+length-1,i+2*length-1);
        i=i+2*length;
    }
    if(i+length-1<n-1)
        merge_(r,r1,i,i+length-1,n-1);
    else
        for(j=i;j<n;j++) r1[j]=r[j];
}//两个两个的归并
void mergesort(int r[])
{
    int length;
    length=1;
    while(length<n){
        mergepass(r,r1,length);
        length=2*length;
        mergepass(r1,r,length);
        length=2*length;
    }
}//归并;
int main()
{
    cin>>n;
    for(int i=0;i<n;i++)
        cin>>r[i];
    mergesort(r);
    for(int i=0;i<n;i++)
        cout<<r[i]<<' ';
    return 0;
}

个人感觉归并排序是快排的逆运算，优点是没有栈的，速度比快排快；

来源：CSDN

作者：兔崽子飞飞飞

链接：https://blog.csdn.net/weixin_44336971/article/details/103484911