求助，改了好久没成功

#include<bits/stdc++.h>
using namespace std;
long long n,m,h,a[1000005],s,d;
int main()
{
	//freopen(".in","r",stdin);
	//freopen(".out","w",stdout);
    ios::sync_with_stdio(0),cin.tie(0);
    ios::sync_with_stdio(0),cout.tie(0);
    a[0]=-1;
    cin>>n>>m;
    for(int i=1;i<=n;i++)
	   cin>>a[i];
	sort(a+1,a+n+1);
	if(m==0){
		cout<<a[n];
		return 0;
	}
	h=a[n];
	while(s<=m){
		h--;
		while(h<a[n-d]&&d<n)d++;
		s+=d;
	}
    h+1;
	cout<<h;
	return 0;
}