稳定
时间复杂度(Olog2n)
空间复杂度(on)

#include <iostream>
using namespace std;
const int N=100010;
int q[N],tmp[N];
int n;
void merge(int q[],int l,int r)
{
    if(l>=r)return;
    int mid=(l+r)>>1;
    merge(q,l,mid);merge(q,mid+1,r);
    int i=l,j=mid+1,k=0;
    while((i<=mid)&&(j<=r))
    {
        if(q[i]<q[j])tmp[k++]=q[i++];
        else tmp[k++]=q[j++];
    }
    while(i<=mid)tmp[k++]=q[i++];
    while(j<=r)tmp[k++]=q[j++];
    for(int i=l,j=0;i<=r;i++,j++)
    {
        q[i]=tmp[j];
    }
}
int main()
{
    cin>>n;
    for(int i=0;i<n;++i)
    {
        scanf("%d",&q[i]);
    }
    merge(q,0,n-1);
    for(int i=0;i<n;i++)
    {
        printf("%d ",q[i]);
    }
    return 0;
}