Find triplets with zero sum

Problem Statement - link #

Given an array arr[] of n integers. Check whether it contains a triplet that sums up to zero.

Your Task: You don’t need to read input or print anything. Your task is to complete the boolean function findTriplets() which takes the array arr[] and the size of the array (n) as inputs and print 1 if the function returns true else print 0 if the function returns false.

Expected Time Complexity: O(n^2)
Expected Auxiliary Space: O(1)

Examples #

Example 1:

Input: n = 5, arr[] = {0, -1, 2, -3, 1}
Output: 1
Explanation: 0, -1 and 1 forms a triplet
with sum equal to 0.

Example 2:

Input: n = 3, arr[] = {1, 2, 3}
Output: 0
Explanation: No triplet with zero sum exists. 

Constraints #

• 1 <= n <= 10^4
• -10^6 <= arr[i] = 10^6

Solutions #

class Solution{
    public:
    //Function to find triplets with zero sum.
    bool findTriplets(int arr[], int n)
    { 
        //Your code here
        sort(arr, arr+n);
        for(int i=n-1; i>=2; i-- ){
            int l = 0, h = i-1;
            int t = -arr[i];
            while(l<h){
                if(arr[l]+arr[h] == t) return 1;
                else if(arr[l] + arr[h] < t) l++;
                else h--;
            }
        }
        return 0; 
    }
};