import java.util.Arrays;

public class ThreeSum {
    public static int threeSumCubic(int[] arr) {
        int count = 0;
        for (int i=0; i<arr.length; i++) {
            for (int j=i+1; j<arr.length; j++) {
                for (int k=j+1; k<arr.length; k++) {
                    if (arr[i] + arr[j] + arr[k] == 0) {
                        count++;
                    }
                }
            }
        }
        return count;
    }

    public static int threeSumQuadratic(int[] arr) {
        Arrays.sort(arr);
        int count = 0;
        for (int i=0; i<arr.length-2; i++) {
            int j = i+1;
            int k = arr.length-1;
            while (j < k) {
                int sum = arr[i] + arr[j] + arr[k];
                if (sum < 0) {
                    j++;
                } else if (sum > 0) {
                    k--;
                } else {
                    count++;
                    j++;
                    k--;
                }
            }
        }
        return count;
    }

    public static void main(String[] args) {
        int[] arr = new int[]{0, 0, 0, 0};
        System.out.println(threeSumQuadratic(arr));
        System.out.println(threeSumCubic(arr));
    }
}