思路

直接找最大长度 –> 判断某个长度是否符合且最大:浮点数二分

拓展

1. 整数二分:两个模板
2. 浮点数二分:一个模板

#include <iostream>

using namespace std;

const int N = 100010;
const double eps = 1e-4;

int n, m;
int w[N];

bool check(double mid)
{
    int cnt = 0;
    for(int i = 0; i < n; i ++ )
        cnt += w[i] / mid;
    return cnt >= m;
}

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

    double l = 0, r = 1e9;
    while(r - l > eps)
    {
        double mid = (r + l) / 2;
        if(check(mid)) l = mid;
        else r = mid;
    }
    printf("%.2lf\n", r);
    return 0;
}