River Locks

题目链接：Problem - D - Codeforces

向上取整+思维

向上取整操作：(A+B-1)/B 就是对 A/B 的向上取整

思路：

 

 

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define endl "\n"

int main() {
    ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
    int n;
    ll sum = 0;
    cin >> n;
    vector<ll>a(n + 1),pre(n+1);
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
        sum += a[i], pre[i] = sum;
    }
    int T = 1;
    cin >> T;
    ll maxn = LLONG_MIN;
    for (int i = 1; i <= n; i++)
    {
　　　　　//pre[i]+i-1/i是向上取整操作
        maxn = max(maxn, (pre[i] + i - 1) / i);
    }
    while (T--)
    {
        int x;
        cin >> x;
        if (x < maxn)cout << -1 << endl;
        else cout << (pre[n] + x -1) / x << endl;
    }
    return 0;
}