프로그래머스 타깃 넘버

N = 0
ans = 0

def solution(numbers, target):
    global N 
    N = len(numbers)
    dfs(numbers, target, 0)
    return ans

def dfs(numbers, target, idx ,nums =[]):
    global N
    global ans
    if len(nums) == N:
        if sum(nums) == target:
            ans+=1
        return
    nums.append(numbers[idx])
    dfs(numbers, target, idx+1, nums)
    nums.pop()
    nums.append(numbers[idx] *(-1))
    dfs(numbers, target, idx+1, nums)
    nums.pop()