题解

二分答案好吧

#include <bits/stdc++.h>
using namespace std;
int a[1000010];
int main(){
    long long n,m,sum=0;
    cin >> n >> m;
    for(int i = 1;i <=n;i++) cin >> a[i];
    sort(a+1,a+n+1);
    long long l = 0,r = a[n],mid,ans;
    while(l<=r){
        sum = 0;
        mid = (l+r)/2;
        for(int j = 1;j <=n;j++){
            if(a[j]>mid) sum+=a[j]-mid;
        }if(sum>=m){
            ans = mid;
            l = mid+1;
        }
        else r = mid-1;
    }cout << ans;
    return 0;
}