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LCA Of Binary Tree

Moderate
0/80
Average time to solve is 10m
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Contributed by
74 upvotes
Asked in companies
MyntraTata Consultancy Services (TCS)American Express

Problem statement

You have been given a Binary Tree of distinct integers and two nodes ‘X’ and ‘Y’. You are supposed to return the LCA (Lowest Common Ancestor) of ‘X’ and ‘Y’.


The LCA of ‘X’ and ‘Y’ in the binary tree is the shared ancestor of ‘X’ and ‘Y’ that is located farthest from the root.


Note :
You may assume that given ‘X’ and ‘Y’ definitely exist in the given binary tree.
For example :
For the given binary tree

Example

LCA of ‘X’ and ‘Y’ is highlighted in yellow colour.
Detailed explanation ( Input/output format, Notes, Images )
Sample Input 1 :
1 2 3 4 7 -1 -1 -1 -1 -1 -1
4 7
Sample Output 1 :
2
Explanation of Sample Input 1 :

Example

Sample Input 2 :
1 2 3 -1 -1 -1 -1
2 3
Sample Output 2 :
1
Constraints :
0 <= 'N' <= 3000
0 <= 'DATA' <= 10^4

Where 'DATA' is a node value of the binary tree.

Time Limit: 1 sec
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