POJ 2976 分数规划

#include<iostream>
#include<stdio.h>
#include<cstring>
#include<algorithm>
using namespace std;

int N,K;
struct date
{
    double ai,bi;
}node[1111];
double arr[1111];

bool DO( double mid )
{
    for( int i = 1; i <= N; i++ )
      arr[i] = node[i].ai - mid*node[i].bi;
    sort( &arr[1],&arr[1]+N );
    double ans = 0;
    for( int i = K + 1; i <= N; i++ )
    ans += arr[i];
    if( ans >= 0 )return true;
    return false;
}
int search( double lt,double rt )
{
    double res;
    while( rt - lt >= 0.00001 )
    {
        double mid = ( lt+rt )/2.;
        if( DO( mid ) ){
            res = mid; lt = mid;
        }
        else rt = mid;
    }
    return int((res+0.005)*100.);
}
int main( )
{
    while( scanf("%d%d",&N,&K) )
    {
        if( N == 0 && K == 0 )break;
        for( int i = 1; i <= N; i++ )
           scanf("%lf",&node[i].ai);
        for( int i = 1; i <= N; i++ )
           scanf("%lf",&node[i].bi);
        printf("%d\n",search(0,1000));
    }
}
/*

3 1
5 0 2
5 1 6
4 2
1 2 7 9
5 6 7 9

*/