Class Solution
java.lang.Object
g1301_1400.s1372_longest_zigzag_path_in_a_binary_tree.Solution
1372 - Longest ZigZag Path in a Binary Tree.<p>Medium</p>
<p>You are given the <code>root</code> of a binary tree.</p>
<p>A ZigZag path for a binary tree is defined as follow:</p>
<ul>
<li>Choose <strong>any</strong> node in the binary tree and a direction (right or left).</li>
<li>If the current direction is right, move to the right child of the current node; otherwise, move to the left child.</li>
<li>Change the direction from right to left or from left to right.</li>
<li>Repeat the second and third steps until you can’t move in the tree.</li>
</ul>
<p>Zigzag length is defined as the number of nodes visited - 1. (A single node has a length of 0).</p>
<p>Return <em>the longest <strong>ZigZag</strong> path contained in that tree</em>.</p>
<p><strong>Example 1:</strong></p>
<p><img src="https://assets.leetcode.com/uploads/2020/01/22/sample_1_1702.png" alt="" /></p>
<p><strong>Input:</strong> root = [1,null,1,1,1,null,null,1,1,null,1,null,null,null,1,null,1]</p>
<p><strong>Output:</strong> 3</p>
<p><strong>Explanation:</strong> Longest ZigZag path in blue nodes (right -> left -> right).</p>
<p><strong>Example 2:</strong></p>
<p><img src="https://assets.leetcode.com/uploads/2020/01/22/sample_2_1702.png" alt="" /></p>
<p><strong>Input:</strong> root = [1,1,1,null,1,null,null,1,1,null,1]</p>
<p><strong>Output:</strong> 4</p>
<p><strong>Explanation:</strong> Longest ZigZag path in blue nodes (left -> right -> left -> right).</p>
<p><strong>Example 3:</strong></p>
<p><strong>Input:</strong> root = [1]</p>
<p><strong>Output:</strong> 0</p>
<p><strong>Constraints:</strong></p>
<ul>
<li>The number of nodes in the tree is in the range <code>[1, 5 * 10<sup>4</sup>]</code>.</li>
<li><code>1 <= Node.val <= 100</code></li>
</ul>
-
Constructor Summary
Constructors -
Method Summary
-
Constructor Details
-
Solution
public Solution()
-
-
Method Details
-
longestZigZag
-