NYOJ之题目1058部分和问题

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简单搜索+剪枝

因为考虑到可能会有多个解，所以是将中间过程保存最后才一起打印出来的

AC代码：

  1:

  2: import java.util.ArrayList;

  3: import java.util.List;

  4: import java.util.Scanner;

  5:

  6: public class Main {

  7:

  8: 	public static void main(String[] args) {

  9:

 10: 		Scanner sc=new Scanner(System.in);

 11:

 12: 		while(sc.hasNextInt()){

 13:

 14: 			int n=sc.nextInt();

 15: 			int k=sc.nextInt();

 16:

 17: 			int x[]=new int[n];

 18: 			for(int i=0;i<x.length;i++) x[i]=sc.nextInt();

 19:

 20: 			ans=new StringBuilder();

 21: 			dfs(x,0,k,new ArrayList<Integer>());

 22:

 23: 			System.out.println(ans.length()==0?"NO":ans);

 24: 		}

 25:

 26: 	}

 27:

 28: 	private static StringBuilder ans;

 29:

 30: 	public static void dfs(int x[],int i,int k,List<Integer> trackStack){

 31: 		if(k==0){

 32: 			if(ans.length()==0) ans.append("YES\n");

 33: 			for(int j=0;j<trackStack.size();j++) ans.append(trackStack.get(j)).append(" ");

 34: 			ans.append("\n");

 35: 			return;

 36: 		} else if(i==x.length || k<0) return;

 37:

 38: 		trackStack.add(x[i]);

 39: 		dfs(x,i+1,k-x[i],trackStack);

 40: 		trackStack.remove(trackStack.size()-1);

 41:

 42: 		dfs(x,i+1,k,trackStack);

 43: 	}

 44:

 45: }

题目来源： http://acm.nyist.net/JudgeOnline/problem.php?pid=1058