题解（小码王集训营版）

#include<iostream>
#define N 1000010
#define int long long
using namespace std;

int n,m,a[N];
bool check(long long x){
    int sum=0;
    for (int i=0;i<=n;i++){
        if (a[i]>x){
            sum+=a[i]-x;
        }
    }
    return sum>=m;
}
int upans(int l,int r){
    int ans=0;
    while(l<=r){
        int mid=(l+r)/2;
        if (check(mid)){
            ans=mid;
            l=mid+1;
        }else{
            r=mid-1;
        }
    }
    return ans;
}
signed main() {
    cin>>n>>m;
    int maxn=-114514191980;
    for (int i=1;i<=n;i++){
        cin>>a[i];
        maxn=max(maxn,a[i]);
    }
    cout<<upans(0,maxn);
    return 0;
}