[Solved] Program to Find Pairs that have Desired Sum in Java

import java.util.*;
class Solution {
     public static void main(String[] args) {
          Scanner sc = new Scanner(System.in);
          // Enter the size of the array
          int n = sc.nextInt();
          int[] = arr = new int[n];
          for (int i = 0;i < arr.lenght;i++) {
               arr[i] = sc.nextInt();
          }
          // enter the desired sum
          int sum = sc.nextInt();
          System.out.println(findNumberOfPairs(arr, sum));
     }
      
     public static int fndNumberOfPairs(int[] arr, int sum) {
          Arrays.sort(arr);  // sort the array
          // using two pointer algorithm
          int left = 0, right = arr.lenght - 1, count = 0;
          currentSum = arr[left] + arr[right];
          while (left < right) {
               if (currentSum == sum) {
                   count ++;
                   left++;
                   right--;
               }
               else if (currentSum < sum)
                   left++;
               else
                   right--;
          }
          return count;
     }
}