Lowest Common Ancestor in a Binary Tree

Given a binary tree and two nodes p and q in the tree, find and return their lowest common ancestor (LCA). Each node has a unique value. The tree is not necessarily complete. Implement your solution with O(n) time complexity. Example 1 Input: root = [3,5,1,6,2,0,8,null,null,7,4], p = 5, q = 1 Output: 3 Explanation: The LCA of nodes 5 and 1 is 3. Example 2 Input: root = [3,5,1,6,2,0,8,null,null,7,4], p = 5, q = 4 Output: 5 Explanation: The LCA of nodes 5 and 4 is 5, since a node can be its own LCA. Constraints: Total number of nodes in the tree is less than 10^4; the tree is a binary tree. Example Input 3 5 1 6 2 0 8 null null 7 4 5 1