java.lang.Object
g1301_1400.s1372_longest_zigzag_path_in_a_binary_tree.Solution

public class Solution extends Object
1372 - Longest ZigZag Path in a Binary Tree\. Medium You are given the `root` of a binary tree. A ZigZag path for a binary tree is defined as follow: * Choose **any** node in the binary tree and a direction (right or left). * If the current direction is right, move to the right child of the current node; otherwise, move to the left child. * Change the direction from right to left or from left to right. * Repeat the second and third steps until you can't move in the tree. 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_. **Example 1:** ![](https://assets.leetcode.com/uploads/2020/01/22/sample_1_1702.png) **Input:** root = [1,null,1,1,1,null,null,1,1,null,1,null,null,null,1,null,1] **Output:** 3 **Explanation:** Longest ZigZag path in blue nodes (right -> left -> right). **Example 2:** ![](https://assets.leetcode.com/uploads/2020/01/22/sample_2_1702.png) **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`
  • Constructor Details

    • Solution

      public Solution()
  • Method Details

    • longestZigZag

      public int longestZigZag(TreeNode root)