代码

#include<algorithm>
using namespace std;
void solve(unsigned *a,int l,int r)
{
	if(!(l<r))return;
	if (l+1==r)
	{
		if(a[l]>a[r])swap(a[l],a[r]);
		return;
	} 
	int mid=(l+r)>>1;
	nth_element(a+l,a+mid,a+r+1);
	solve(a,l,mid);solve(a,mid+1,r);
	
}
void sort(unsigned *a, int n){solve(a,0,n-1);}

评测结果