第一

嘻嘻

#include <iostream>
using namespace std;

int nums[100005], n, m;
double pre[100005];

bool check(double average) {
    double minPre = 0;
    for (int i = 1; i <= n; i++) {
        pre[i] = pre[i - 1] + nums[i - 1] - average;
        if (i >= m && pre[i] >= minPre) {
            return true;
        }
        if (i >= m) {
            minPre = min(minPre, pre[i - m + 1]);
        }
    }
    return false;
}

int main() {
    cin >> n >> m;
    
    for (int i = 0; i < n; i++) {
        cin >> nums[i];
    }

    double l = 0, r = 2000;
    for (int i = 0; i < 100; i++) {
        double mid = (l + r) / 2;
        if (check(mid)) {
            l = mid;
        } else {
            r = mid;
        }
    }

    cout << (int) (l * 1000);

    return 0;
}