浮点数二分

#include<iostream>
#include<algorithm>
using namespace std;
const int N = 1e5 + 5;
int len[N];
int n,m;
bool check(double mid) {
    int res = 0;
    for (int i = 0;i < n;i++) {
        res += len[i] / mid;
    }
    return res >= m;
}
int main() {
    cin >> n >> m;
    for (int i = 0;i < n;i++) {
        cin >> len[i];
    }
    double l = 0, r = 1e9;
    while (r - l > 1e-4) {
        double mid = (l + r) / 2;
        if (check(mid)) {
            l = mid;
        } else {
            r = mid;
        }
    }
    printf("%.2lf\n",r);
}