[SWEA] 부분 수열의 합

 

 

[문제]

https://swexpertacademy.com/main/code/problem/problemDetail.do?contestProbId=AV7IzvG6EksDFAXB

SW Expert Academy

 

 

[소스 코드] 

// 1차 코드

import java.util.*;
import java.io.*;
public class Solution {
	static int n,k,result;
	static int[] arr;
	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st;
		int T = Integer.parseInt(br.readLine());
		for(int tc=1;tc<=T;tc++) {
			st = new StringTokenizer(br.readLine());
			n = Integer.parseInt(st.nextToken());
			k = Integer.parseInt(st.nextToken());
			arr = new int[n];
			st = new StringTokenizer(br.readLine());
			for(int i=0;i<n;i++) {
				arr[i] = Integer.parseInt(st.nextToken());
			}
			result = 0;
			for(int i=1;i<=n;i++) {
				select(0,0,i,0);
			}
			System.out.println("#"+tc+" "+result);
		}
	}
	private static void select(int cnt,int idx,int max,int sum) {
		if(cnt==max) {
			if(sum==k) {
				result++;
				return;
			}
		}
		for(int i=idx;i<n;i++) {
			select(cnt+1,i+1,max,sum+arr[i]);
		}
	}
}

// 최종 코드

import java.util.*;
import java.io.*;
public class Solution {
	static int n,k,result;
	static int[] arr;
	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		StringTokenizer st;
		int T = Integer.parseInt(br.readLine());
		for(int tc=1;tc<=T;tc++) {
			st = new StringTokenizer(br.readLine());
			n = Integer.parseInt(st.nextToken());
			k = Integer.parseInt(st.nextToken());
			arr = new int[n];
			st = new StringTokenizer(br.readLine());
			for(int i=0;i<n;i++) {
				arr[i] = Integer.parseInt(st.nextToken());
			}
			result = 0;
			select(0,0);
			System.out.println("#"+tc+" "+result);
		}
	}
	private static void select(int idx,int sum) {
		if(idx==n) {
			if(sum==k) {
				result++;
			}
			return;
		}
		select(idx+1,sum+arr[idx]);
		select(idx+1,sum);
	}
}