题解 | 紧急支援

#include<iostream>
using namespace std;
int main() {
    int n, k, h;
    cin >> n >> k >> h;
    int nums[n - 1];
    long long ans = 0;
    for (int i = 0; i < n - 1; i++) {
        cin >> nums[i];
        ans += nums[i];
    }
    long long max = 0, sum = 0;
    for (int i = 0; i < n - 1; i++) {
        if (i < k) sum += nums[i];
        else {
            if (sum > max) max = sum;
            sum += nums[i] - nums[i - k];
        }
    }
    if (max >= 2 * h) cout << ans - (max - 2 * h) << endl;
    else cout << ans << endl;
    return 0;
}