hdu 1551 Cable master 二分

 

/*
 * hdu1511.c
 *
 *  Created on: 2011-10-9
 *      Author: bjfuwangzhu
 */

#include<stdio.h>
#include<math.h>
#define eps 1.0e-8
#define nmax 10001
double num[nmax];
int cmp(int n, double aver) {
    int i, temp;
    for (i = 0, temp = 0; i < n; i++) {
        temp += (int) (num[i] / aver);
    }
    return temp;
}
void solve(int n, int k, double sum) {
    double left, right, mid;
    left = 0, right = sum / k, mid = 0.0;
    while (fabs(left - right) > eps) {
        mid = (left + right) / 2;
        if (cmp(n, mid) >= k) {
            left = mid;
        } else {
            right = mid;
        }
    }
    printf("%.2lf\n", mid);
}
int main() {
#ifndef ONLINE_JUDGE
    freopen("data.in", "r", stdin);
#endif
    int n, k, i;
    double sum;
    while (~scanf("%d %d", &n, &k) && (n || k)) {
        for (i = 0, sum = 0; i < n; i++) {
            scanf("%lf", num + i);
            sum += num[i];
        }
        solve(n, k, sum);

    }
    return 0;
}