[swexpert] 9229. 한빈이와 Spot Mart (D3, java)

조합 문제이다. nC2를 구하면 된다.

import java.util.Scanner;

public class Solution {
	static int t;
	static int n,m;
	static int[] snack;
	static int answer;
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		t=sc.nextInt();
		for (int tc = 1; tc <=t; tc++) {
			n=Integer.parseInt(sc.next());
			m=Integer.parseInt(sc.next());
			answer=Integer.MIN_VALUE;
			snack=new int[n];
			for (int i = 0; i < n; i++) {
				snack[i]=Integer.parseInt(sc.next());
			}
			check(0,0,0);
			System.out.printf("#%d %d\n",tc,answer<0?-1:answer);
		}
		
	}
	private static void check(int cnt,int weight,int start) {
		if(cnt==2) {
			if(weight>answer)answer=weight;
			return;
		}
		for (int i = start; i < n; i++) {
			if(weight+snack[i]<=m) {
				check(cnt+1,weight+snack[i],i+1);
			}
		}
	}
}