Solution: Lowest Common Ancestor of a Binary Tree III

Explore the two-pointer technique to find the lowest common ancestor of two nodes in a binary tree when parent references are available. Understand how by moving pointers up the tree and switching start points, you can efficiently locate the common ancestor with O(h) time and constant space complexity.

We'll cover the following...

Statement
Solution
- Time complexity
- Space complexity

Statement

You are given two nodes, p and q. The task is to return their lowest common ancestor (LCA). Both nodes have a reference to their parent node. The tree’s root is not provided; you must use the parent pointers to find the nodes’ common ancestor.

Note: The lowest common ancestor of two nodes, p and q, is the lowest node in the binary tree, with both p and q as descendants.
In a tree, a descendant of a node is any node reachable by following edges downward from that node, including the node itself. ...