poj2976 Dropping tests

Posted 2020-12-27 akcqhzdy

01分数规划裸题

为毛二分一定要打成r=mid这么恶心啊

#include<cstdio>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<cmath>
using namespace std;
typedef long long LL;

int n,k;
double a[1100],b[1100],c[1100];
double check(double mid)
{
    for(int i=1;i<=n;i++)c[i]=a[i]-mid*b[i];
    sort(c+1,c+n+1);
    
    double ret=0;
    for(int i=n;i>k;i--)ret+=c[i];
    return ret;
}
int main()
{
    while(scanf("%d%d",&n,&k)!=EOF)
    {
        if(n==0&&k==0)break;
        
        for(int i=1;i<=n;i++)scanf("%lf",&a[i]);
        for(int i=1;i<=n;i++)scanf("%lf",&b[i]);
        
        double l=0,r=1,ans;
        while(r-l>1e-8)
        {
            double mid=(l+r)/2;
            if(check(mid)>0)
            {
                l=mid;
            }
            else r=mid;
        }
        printf("%.0lf
",r*100);
    }
    return 0;
}