题解归档 - cf104077J

本文由 cf-code 本地题解库自动归档；公开内容以本地 AC/验证版本为准。

• 本地编号：cf104077J
• 本地来源：problems/cf104077J/idea.md
• 题目链接：https://codeforces.com/gym/104077/problem/J
• 原始标题：J - Strange Sum

思路

J - Strange Sum

At most two elements can be selected.

If three elements were selected, take the selected element with the largest index i. The interval
[1,i] has length i and contains all selected elements up to that largest one, hence at least
three selected elements. This violates the condition for selecting a_i.

So the answer is just the sum of the largest two positive values, or fewer if positives are absent.

代码

来源：problems/cf104077J/solution.cpp

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    ll best1 = 0, best2 = 0;
    for (int i = 1; i <= n; i++) {
        ll x;
        cin >> x;
        if (x > best1) {
            best2 = best1;
            best1 = x;
        } else if (x > best2) {
            best2 = x;
        }
    }
    cout << best1 + best2 << '\n';
    return 0;
}