class Solution {
public int solution(int[] number) {
int answer = 0;
for(int i = 0; i < number.length; i++){
int first = number[i];
for(int j = i+1; j < number.length; j++){
int second = number[j];
for(int k = j+1; k < number.length; k++){
int third = number[k];
if(first + second + third == 0){
answer++;
}
}
}
}
return answer;
}
}
3중 for문으로 간단하게 풀 수 있었다