Codeforces Round #251 (Div. 2) A - Devu, the Singer and Churu, the Joker

水题

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main(){
    int n,d,t;
    cin >> n >> d;
    for(int i =  ; i < n; ++ i){
        cin >> t;
        d-=t;
    }
    d-=(n-)*;
    if(d < ) cout<<-<<endl;
    else cout<<(n-)*+d/<<endl;
}