- Difficulty: Medium
- Tags: LeetCode, Medium, Tree, Depth-First Search, Breadth-First Search, Hash Table, Binary Tree, leetcode-1740, O(n), O(h)
Problem
Given the root of a binary tree and two integers p
and q
, return the distance between the nodes of value p
and value q
in the tree.
The distance between two nodes is the number of edges on the path from one to the other.
Example 1:
Input: root = [3,5,1,6,2,0,8,null,null,7,4], p = 5, q = 0 Output: 3 Explanation: There are 3 edges between 5 and 0: 5-3-1-0.
Example 2:
Input: root = [3,5,1,6,2,0,8,null,null,7,4], p = 5, q = 7 Output: 2 Explanation: There are 2 edges between 5 and 7: 5-2-7.
Example 3:
Input: root = [3,5,1,6,2,0,8,null,null,7,4], p = 5, q = 5 Output: 0 Explanation: The distance between a node and itself is 0.
Constraints:
- The number of nodes in the tree is in the range
[1, 104]
. 0 <= Node.val <= 109
- All
Node.val
are unique. p
andq
are values in the tree.