[JavaScript] 프로그래머스 타겟넘버 LEVEL2

문제출처

let answer = 0;

const dfs = (numbers, target, sum, cnt) => {
    if (cnt === numbers.length) {
        if (sum === target) answer++;
        return;
    }
    
    dfs(numbers, target, sum + numbers[cnt], cnt + 1);
    dfs(numbers, target, sum - numbers[cnt], cnt + 1);
};

function solution(numbers, target) {
    dfs(numbers, target, numbers[0], 1);
    dfs(numbers, target, -numbers[0], 1);
    
    return answer;
}