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 pointers are given. Understand how moving pointers up to their parents and switching starting points leads to identifying the common ancestor efficiently with O(1) space and O(h) time 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. ...