235. Lowest Common Ancestor of a Binary Search Tree
Medium
Given a binary search tree (BST), find the lowest common ancestor (LCA) node of two given nodes in the BST.
According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes p
and q
as the lowest node in T
that has both p
and q
as descendants (where we allow a node to be a descendant of itself).”
Example 1:
Example 2:
Example 3:
Constraints:
The number of nodes in the tree is in the range
[2, 105]
.-109 <= Node.val <= 109
All
Node.val
are unique.p != q
p
andq
will exist in the BST.
解題
這題利用 BST 左邊子樹必定比 root 小、右邊子樹必定比 root 大的特性來解,不需要使用 recursive,是很漂亮的題目。
Last updated