POJ 1064 Cable master 二分

#include <cstdio>
#include <cmath>
using namespace std;
const int maxn = 10005;
const double inf = 200005.0;
double a[maxn];
const double eps = 1e-5;
int n,k;
bool ok(double x) {
    int num = 0;
    for(int i = 0; i < n; i++)
        num += (int)(a[i]/x);
    return num >= k;
}
void solve() {
    double low = 0;
    double high = inf;
    while( high-low > eps ) {
        double mid = (high+low)*0.5;
        if( ok(mid)) low = mid;
        else high = mid;
    }
    printf( "%.2f\n", floor(high*100)/100 );
}
int main() {
    while( scanf( "%d%d", &n, &k ) == 2 ) {
        for( int i = 0; i < n; i++ ){
            scanf( "%lf", a+i );
        }
        solve();
    }
    return 0;
}