Solution: Lowest Common Ancestor of a Binary Tree III

Understand how to identify the lowest common ancestor of two nodes in a binary tree when given parent references. Explore a two-pointer technique where pointers move up the tree from each node and switch starting points to meet at the common ancestor. This lesson helps you implement an efficient traversal strategy with O(h) time and constant space complexity.

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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. ...