🚀 Feature Request: Add "Lowest Common Ancestor (LCA) of a Binary Tree" (LeetCode #236)

🧩 Description

I would like to contribute the implementation of the Lowest Common Ancestor (LCA) of a Binary Tree problem.
This algorithm finds the lowest (or deepest) node in a binary tree that is an ancestor of two given nodes.

🧠 Problem Statement

Given a binary tree and two nodes p and q, find their lowest common ancestor (LCA).
The LCA of two nodes p and q is the lowest node in the tree that has both p and q as descendants (a node can be a descendant of itself).

📘 LeetCode Reference: Problem #236 – Lowest Common Ancestor of a Binary Tree

⚙️ Approach

• Use a recursive approach:
  1. If the current node is null, return null.
  2. If the current node matches either p or q, return the current node.
  3. Recursively search for LCA in the left and right subtrees.
  4. If both sides return non-null, the current node is the LCA.
  5. Otherwise, return the non-null result.

🧮 Time and Space Complexity

• Time Complexity: O(N), where N is the number of nodes in the tree.
• Space Complexity: O(H), where H is the height of the tree (due to recursion stack).

💻 Language

• Java

✅ Checklist

• I have read the contribution guidelines.
• My code follows the repository’s coding style.
• I will add proper test cases and comments.