1372. Longest ZigZag Path in a Binary Tree
Medium
30 Points
Dynamic Programming
Tree
Depth-First Search
Binary Tree
You are given the root of a binary tree.
A ZigZag path for a binary tree is defined as follow:
Zigzag length is defined as the number of nodes visited - 1. (A single node has a length of 0).
Return the longest ZigZag path contained in that tree.
Examples
Example 1
Input: root = [1,null,1,1,1,null,null,1,1,null,1,null,null,null,1]
Output: 3
Explanation: Longest ZigZag path in blue nodes (right -> left -> right).
Example 2
Input: root = [1,1,1,null,1,null,null,1,1,null,1]
Output: 4
Explanation: Longest ZigZag path in blue nodes (left -> right -> left -> right).
Example 3
Input: root = [1]
Output: 0
Constraints
The number of nodes in the tree is in the range [1, 5 * 104].1 <= Node.val <= 100
1372. Longest ZigZag Path in a Binary Tree
Medium
30 Points
Dynamic Programming
Tree
Depth-First Search
Binary Tree
You are given the root of a binary tree.
A ZigZag path for a binary tree is defined as follow:
Zigzag length is defined as the number of nodes visited - 1. (A single node has a length of 0).
Return the longest ZigZag path contained in that tree.
Examples
Example 1
Input: root = [1,null,1,1,1,null,null,1,1,null,1,null,null,null,1]
Output: 3
Explanation: Longest ZigZag path in blue nodes (right -> left -> right).
Example 2
Input: root = [1,1,1,null,1,null,null,1,1,null,1]
Output: 4
Explanation: Longest ZigZag path in blue nodes (left -> right -> left -> right).
Example 3
Input: root = [1]
Output: 0
Constraints
The number of nodes in the tree is in the range [1, 5 * 104].1 <= Node.val <= 100