p122.java

/*Given an array arr of size n and an integer X. Find if there's a triplet in the array which sums up to the given integer X.


Example 1:

Input:
n = 6, X = 13
arr[] = [1 4 45 6 10 8]
Output:
1
Explanation:
The triplet {1, 4, 8} in 
the array sums up to 13.
Example 2:

Input:
n = 5, X = 10
arr[] = [1 2 4 3 6]
Output:
1
Explanation:
The triplet {1, 3, 6} in 
the array sums up to 10.

Your Task:
You don't need to read input or print anything. Your task is to complete the function find3Numbers() which takes the array arr[], the size of the array (n) and the sum (X) as inputs and returns True if there exists a triplet in the array arr[] which sums up to X and False otherwise.


Expected Time Complexity: O(n2)
Expected Auxiliary Space: O(1)


Constraints:
1 ≤ n ≤ 103
1 ≤ A[i] ≤ 105*/
class Solution{
    public static boolean find3Numbers(int A[], int n, int X) { 
        Arrays.sort(A);
        for(int i=0;i<n;i++){
            int l=i+1;
            int r=n-1;
            while(l<r){
                if(A[i]+A[l]+A[r]==X){
                    return true;
                }else if(A[i]+A[l]+A[r]<X){
                    l++;
                }else{
                    r--;
                }
            }
        }
        return false;
    }
}