[프로그래머스] 삼총사

class Solution {
    public int solution(int[] number) {
        int answer = 0;
        
        for(int i=0; i<number.length; i++){
            for(int j= i+1; j<number.length; j++){
                for(int k= j+1; k<number.length; k++){
                    int sum = number[i]+ number[j]+ number[k];
                    if(sum == 0){
                        answer++;
                    }
                }
            }
        }
        return answer;
    }
}