Given a BST and an integer K. Find the Kth Smallest element in the BST.
Example 1:
Input:
2
/ \
1 3
K = 2
Output: 2
Example 2:
Input:
2
/ \
1 3
K = 5
Output: -1
Your Task:
You don't need to read input or print anything. Your task is to complete the function KthSmallestElement() which takes the root of the BST and integer K as inputs and return the Kth smallest element in the BST, if no such element exists return -1.
Expected Time Complexity: O(N).
Expected Auxiliary Space: O(1).
Constraints:
1<=Number of nodes<=100000
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Input Format:
The tree in the input is given in the form of a string as described below.
The values in the string are in the order of level order traversal of the tree where, numbers denotes node values, and a character “N” denotes NULL child.
For example:
For the above tree, the string will be: 1 2 3 N N 4 6 N 5 N N 7 N
The first line contains a String S denoting the binary tree. The second line contains an integer K.
Example:
2 1 3 2
Input Format:
The tree in the input is given in the form of a string as described below.
The values in the string are in the order of level order traversal of the tree where, numbers denotes node values, and a character “N” denotes NULL child.
For example:
For the above tree, the string will be: 1 2 3 N N 4 6 N 5 N N 7 N
The first line contains a String S denoting the binary tree. The second line contains an integer K.
Example:
2 1 3 2