알고리즘풀이_ 프로그래머스 타겟넘버 java

class Solution {
    static int endIndex;
    static int answer;
    public static void recursion(int i, int sign, int target, int[] numbers, int sum) {
         if(i > endIndex) return;
         sum += (sign * numbers[i]);
         if(i == endIndex) {
             if(target != sum) return;
             answer++;
             return;
         }
        
        recursion(i+1, 1, target, numbers, sum);
        recursion(i+1, -1, target, numbers, sum);
    }
    
    public int solution(int[] numbers, int target) {
        answer = 0;
        endIndex = numbers.length-1;
        
        recursion(0, 1, target, numbers, 0);
        recursion(0, -1, target, numbers, 0);

        return answer;
    }
}