Given a Binary Search Tree and a target number target. Write a program to check if there exist two elements in the BST such that their sum is equal to the given target.

Problem Note

• If the two elements exist in BST with the target sum, return 1, else return 0.

Example 1

Input: Below is the given BST.
       30
      /  \
    15    60
   / \    / \
  7   22 45  75
 / \
17   27

target = 49
Output: 1
Explanation: The sum of the elements 22 and 27 is equal to 49.

Example 2

Input: Below is the given BST.
        30
       /  \
     15    60
    / \    / \
   7   22 45  75
  / \
 17  27

target = 5
Output: 0
Explanation: There is no two elements whose sum is equal to 5.