Medium · Trees

Lowest Common Ancestor of a Binary Tree

Given a binary tree as a level-order array tree (null marks a missing node) and two indices p and q of distinct nodes in that array, return the lowest common ancestor of those two nodes: the deepest node whose subtree contains both (a node is in its own subtree).

tree=[3,5,1,6,2,0,8,null,null,7,4], p=5, q=1

tree=[3,5,1,6,2,0,8,null,null,7,4], p=5, q=4