二分基础题

2146 分割绳子http://www.51nod.com/Challenge/Problem.html#problemId=2146

#include <bits/stdc++.h>
using namespace std;
double a[1005];
int n,k;
int check(double x){
    int num = 0;
    for(int i = 0; i < n; i++)
       num += (int)(a[i] / x);
    return num >= k;
}
int main(){
    //freopen("in","r",stdin);
    cin >> n >> k;
    double l = 0,r = 0;
    for(int i = 0; i < n; i++){
        cin >> a[i];
        r += a[i];
    }
    for(int i = 0; i < 100; i++){
        double mid = (l + r) / 2;
        if(check(mid)) l= mid;
        else r = mid;
    }
    printf("%.2lf",r);
    return 0;
}

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