Kth Largest in BST

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 https://workat.tech/problem-solving/practice/kth-largest-element-bst

Given the root node of a binary search tree and a number k, find out the kth largest element (1-indexed) in the BST.

Note: You can assume that k <= number of nodes.

Testing

Input Format

The first line contains an integer T denoting the number of test cases.

For each test case, the input has 2 lines:

  • The first line contains an integer n denoting the number of nodes in the tree (including the NULL nodes).
  • The second line contains n space-separated integers that will form the binary tree. The integers follow level order traversal of the tree where -1 indicates a NULL node.
  • The third line contains an integer k.

Output Format

For each test case, the output contains an integer with the value of the kth largest element in BST.

Sample Input

4
9
2 1 3 -1 -1 -1 5 4 7
4
7
6 3 21 -1 -1 -1 89
1
12
8 3 9 -1 4 -1 10 -1 -1 -1 12 11
7
4
28 14 -1 11
2

Expected Output

3
89
3
14

1 <= T <= 10
1 <= n <= 105
1 <= node value <= 109

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