c++归并排序

#include <iostream>
using namespace std;
#include <string.h>
#include <vector>
void merge(int low,int mid,int high,vector<int>& ans,vector<int>& tem){
    int l = low;
    int h = mid + 1;
    int k = low;
    while(l <= mid && h <= high){
        if(ans[l] < ans[h])
            tem[k++] = ans[l++];
        else
            tem[k++] = ans[h++];
    }
    while(l <= mid)
        tem[k++] = ans[l++];
    while(h <= high)
        tem[k++] = ans[h++];

    for(int i = low;i <= high;i++)
        ans[i] = tem[i];
}

void mergesort(int low,int high,vector<int>& ans,vector<int>& tem){
/*归*/
    if(low >= high)
        return ;
    int mid = low + (high - low) / 2;
    mergesort(low,mid,ans,tem);
    mergesort(mid+1,high,ans,tem);
/*并*/
    merge(low,mid,high,ans,tem);
}


int main()
{
    vector<int> ans = {20,10,49,23,1,39,76,58,19,30};
    vector<int> tem(10,0);
    int n = ans.size() - 1;
    mergesort(0,n,ans,tem);

    for(int i : ans)
        cout<<i<<endl;
    return 0 ;
}