HDOJ FatMouse' Trade JAVA 1009

简单的贪心问题

但不知道为什么 用Decimal输出的不能AC 

只能用printf的格式输出，AC了

package _1009;

import java.text.DecimalFormat;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;

class jf implements Comparable<jf>{
	int j,f;
	double avg;
	jf(int a,int b,double c){
		j=a;f=b;avg=c;
	}
	public int compareTo(jf o) {
		if(this.avg-o.avg > 0.001)
			return -1;
		else
			return 1;
	}
}

public class Main {
	static List<jf> list ;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		while(sc.hasNext()){
			int m = sc.nextInt();
			int n = sc.nextInt();
			if(m==-1&&n==-1) break;
			list = new LinkedList<jf>();

			for (int i = 0; i < n; i++) {
				int j,f;
				j = sc.nextInt();
				f = sc.nextInt();
				list.add(new jf(j,f,(double)j/f));
			}
			Collections.sort(list);
			double sum = 0;
			for (int i = 0; i < list.size(); i++) {
				if(m>=list.get(i).f){
					sum += list.get(i).j;
					m -= list.get(i).f;
				}else{
					sum += list.get(i).avg*m;
					break;
				}
			}
//			DecimalFormat df = new DecimalFormat("0.000");
//			System.out.println(df.format(sum));
			System.out.printf("%.3f",sum);
			System.out.println();
		}
	}
}

FatMouse' Trade

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 83869    Accepted Submission(s): 29046

Problem Description

FatMouse prepared M pounds of cat food, ready to trade with the cats guarding the warehouse containing his favorite food, JavaBean.
The warehouse has N rooms. The i-th room contains J[i] pounds of JavaBeans and requires F[i] pounds of cat food. FatMouse does not have to trade for all the JavaBeans in the room, instead, he may get J[i]* a% pounds of JavaBeans if he pays F[i]* a% pounds of cat food. Here a is a real number. Now he is assigning this homework to you: tell him the maximum amount of JavaBeans he can obtain.

 

Input

The input consists of multiple test cases. Each test case begins with a line containing two non-negative integers M and N. Then N lines follow, each contains two non-negative integers J[i] and F[i] respectively. The last test case is followed by two -1's. All integers are not greater than 1000.

 

Output

For each test case, print in a single line a real number accurate up to 3 decimal places, which is the maximum amount of JavaBeans that FatMouse can obtain.

 

Sample Input

  

   5 3
7 2
4 3
5 2
20 3
25 18
24 15
15 10
-1 -1
  

 

Sample Output

  

   13.333
31.500
  

 

Author

CHEN, Yue

 

Source

ZJCPC2004

 

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