javascript - 타겟 넘버

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

프로그래머스

function solution(numbers, target) {
    var answer = 0;
    
    function dfs (num, index) {
        if (index === numbers.length) {
            if (num === target) answer++;
            return;
        }
        dfs(num + numbers[index], index+1);
        dfs(num - numbers[index], index+1);
    }
    
    dfs(0, 0);
    
    return answer;
}