Programmers LV.2 타겟넘버

static int answer =0;

    @org.junit.Test
    public void targetNumber(){
        int[] numbers = {1,1,1,1,1};
        int target = 3;


        dfs(numbers, 0, target);
        System.out.println(answer);

    }

    public void dfs(int[] numbers , int index , int target){

        if(index == numbers.length){
            int sum = 0;
            for(int i=0; i<numbers.length; i++)
                sum += numbers[i];

            answer += (sum == target) ? 1 : 0;
            return;
        }

        dfs(numbers,index+1,target);
        System.out.println("first index" + (index+1));

        numbers[index] *= -1;

        System.out.println("numbers " +  numbers[index]);

        dfs(numbers,index+1,target);

        System.out.println("last index" + (index+1));
    }

 

DFS 사용해서 + / - 를 index 별로 변경하여 확인 후 answer 출력