模板——归并排序

/*
 * @Description: To iterate is human, to recurse divine.
 * @Autor: Recursion
 * @Date: 2022-03-24 17:31:27
 * @LastEditTime: 2022-03-24 17:56:03
 */
#include<bits/stdc++.h>
using namespace std;
const int N = 1e6 + 10;
int a[N],b[N];

void merge(int low,int mid,int high)
{
    int i = low,j = mid + 1,k = low;
    while(i <= mid&&j <= high){
        if(a[i] < a[j])
            b[k++] = a[i++];
        else
            b[k++] = a[j++];
    }
    while(i <= mid)
        b[k++] = a[i++];
    while(j <= high)
        b[k++] = a[j++];
    for(int i = low;i <= high;i++)
        a[i] = b[i];
}

void mergesort(int low,int high)
{
    int mid = (low + high)/2;
    if(low >= high) return;
    mergesort(low,mid);
    mergesort(mid + 1,high);
    merge(low,mid,high);
}

int main()
{
    int n;
    while(cin >> n){
        for(int i = 1;i <= n;i ++)
            cin >> a[i];
        mergesort(1,n);
        for(int i = 1;i <= n;i ++)
            cout << a[i] << endl;
    }
}