ThreeSum.java

package com.sarvesh.javabasics;
import java.util.*;

public class ThreeSum {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter number of elements: ");
        int n = sc.nextInt();

        int[] arr = new int[n];
        System.out.println("Enter elements:");
        for(int i = 0; i < n; i++) {
            arr[i] = sc.nextInt();
        }
        Arrays.sort(arr);
        for(int i = 0; i < n - 2; i++) {
            if(i > 0 && arr[i] == arr[i - 1]) continue;
            int left = i + 1;
            int right = n - 1;
            while(left < right) {
                int sum = arr[i] + arr[left] + arr[right];
                if(sum == 0) {
                    System.out.println(arr[i] + " " + arr[left] + " " + arr[right]);
                    while(left < right && arr[left] == arr[left + 1]) left++;
                    while(left < right && arr[right] == arr[right - 1]) right--;
                    left++;
                    right--;
                } else if(sum < 0) {
                    left++;
                } else {
                    right--;
                }
            }
        }
        sc.close();
    }
}