Find a pair with given target in BST
Medium Accuracy: 47.17% Submissions: 30068 Points: 4

Given a Binary Search Tree and a target sum. Check whether there's a pair of Nodes in the BST with value summing up to the target sum.

Example 1:

Input:
2
/   \
1     3
sum = 5
Output: 1
Explanation:
Nodes with value 2 and 3 sum up to 5.


Example 2:

Input:
6
/
5
/
3
/  \
1    4
sum = 2
Output: 0
Explanation:
There's no pair that sums up to 2.


isPairPresent() that takes a root node and a target value as a parameter and returns 1 if there's a pair of Nodes in the BST with values summing up to the target sum, else returns 0.

Expected Time Complexity: O(N).
Expected Auxiliary Space: O(Height of the BST).

Constraints:
1 ≤ Number of Nodes ≤ 105
1 ≤ Sum ≤ 106

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