1 #include <iostream> 2 #include <iomanip>  3 #include <cmath> 4 using namespace std; 5  6 int N; 7 int K; 8 double num[10001]; 9 10 int calc(double len)11 {12     int numK= 0;13     for(int i = 0; i < N; ++i)14     {15         numK += (int)(num[i] / len);    16     }17     return numK;18 }19 20 double solve()21 {22     double low = 0;23     double upper = 100000;24     int count  = 0;25     double mid;26     int numK;27     while(count < 100)28     {29         mid = (low + upper) / 2;30         numK = calc(mid);31         if(numK >= K)32             low = mid;    33         else34             upper = mid;35         ++count;    36     }37     return mid;38 }39 40 int main()41 {42     //基于二分法的思想实现 43     cin >> N >> K;44     for(int i = 0; i < N; ++i)45         cin >> num[i];46         //这里floor很重要 47     cout << setiosflags(ios::fixed) << setprecision(2) << floor(solve()*100)/100 << endl;48     return 0;49 }