[BFS,DFS] 프로그래머스 - 타겟넘버

-문제

https://school.programmers.co.kr/learn/courses/30/lessons/43165.

프로그래머스

 

 

-자바

class Solution {
    public int solution(int[] numbers, int target) {
        int answer = 0;
        
        answer = 
            dfs(numbers, target, numbers[0], 1) + 
            dfs(numbers, target, -numbers[0], 1);
        
        return answer;
    }
    
    public int dfs(int[] numbers, int target, int sum, int i) {
        
        if(i == numbers.length) {
            if(sum == target) {
                return 1;
            } else {
                return 0;
            }
        }
        
        int result = 0;
        result += dfs(numbers, target, sum+numbers[i], i+1);
        result += dfs(numbers, target, sum-numbers[i], i+1);
        return result;
    }
}