Solution: Lowest Common Ancestor of a Binary Tree III
Understand how to identify the lowest common ancestor of two nodes in a binary tree without a root reference. Learn to use a two-pointer approach, moving pointers up the tree via parent nodes until they meet. This method handles different depths and uses constant space, providing an efficient solution for tree ancestor problems.
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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,
pandq, is the lowest node in the binary tree, with bothpandqas descendants.In a tree, a descendant of a node is any node reachable by following edges downward from that node, including the node itself.
Constraints:
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