poj 2976 基础01分数规划

　　这个题算是01分数规划的最基本的应用了， 01分数规划是给你n对数(a1, b1)....(an, bn), 然后让你选择一些数对， 使得sigma(ai)/sigma(bi)最大。这里附上讲解一份， http://blog.csdn.net/hhaile/article/details/8883652， 代码如下：

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <cmath>using namespace std;
typedef long long LL;
const int maxn = 1000 + 10;
const double eps = 1e-4;
int n, k;
double ai[maxn], bi[maxn];
double ci[maxn];double check(double mid)
{for(int i=0; i<n; i++) ci[i] = ai[i]*100 - mid*bi[i];sort(ci, ci+n);double res = 0.0;for(int i=k; i<n; i++) res += ci[i];return res;
}int main()
{while(cin>>n>>k){if(n==0 && k==0) break;for(int i=0; i<n; i++) scanf("%lf", &ai[i]);for(int i=0; i<n; i++) scanf("%lf", &bi[i]);double l=0.0, r=100;double ans;while(r-l > eps){double mid = (l+r)/2;if(check(mid) >= -eps) l=ans=mid;else r=mid;}printf("%.0f\n", ans);}return 0;
}