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