1372. Longest ZigZag Path in a Binary Tree

Author: VinayByte

1372.LongestZigZagPathinaBinaryTree.kt

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+/**
+ * Example:
+ * var ti = TreeNode(5)
+ * var v = ti.`val`
+ * Definition for a binary tree node.
+ * class TreeNode(var `val`: Int) {
+ *     var left: TreeNode? = null
+ *     var right: TreeNode? = null
+ * }
+ */
+ //https://leetcode.com/problems/longest-zigzag-path-in-a-binary-tree/description
+class Solution {
+    var longestPath = 0
+    fun longestZigZag(root: TreeNode?): Int {
+        dfs(root, 0, 0)
+        return longestPath
+    }
+
+    fun dfs(node: TreeNode?, leftLength: Int, rightLength: Int){
+        if (node == null) {
+            return
+        }
+        longestPath = maxOf(longestPath, maxOf(leftLength, rightLength))
+        dfs(node.left, rightLength + 1, 0)
+        dfs(node.right, 0, leftLength + 1)
+    }
+}