POj 2976

题目分析：01分数规划

import java.text.DecimalFormat;import java.util.Arrays;import java.util.Scanner;public class Main{public static void main(String[] args) {Scanner scanner = new Scanner(System.in);while(scanner.hasNext()) {int N = scanner.nextInt();int k = scanner.nextInt();if(N == 0 && k ==0) continue;int[] a = new int[N];int[] b = new int[N];for(int i = 0; i < N; i++) {a[i] = scanner.nextInt();}for(int i = 0; i < N; i++) {b[i] = scanner.nextInt();}double L = 0.0;double R = 1.0;double[] f = new double[N];double mid = 0.0;while(Math.abs(L-R) > Math.pow(10, -6)) {mid = (L+R)/2;for(int i = 0; i < N; i++) {f[i] = a[i] * 1.0 - mid * b[i] * 1.0;}Arrays.sort(f);double sum = 0.0;for(int i = k; i < N; i++) {sum += f[i];}//函数是递减的if(sum > 0) {L = mid;} else if(sum < 0) {R = mid;} else break;}mid *= 100;DecimalFormat format = new DecimalFormat("0");System.out.println(format.format(mid));}}}