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

*/