Untitled
unknown
java
4 years ago
965 B
7
Indexable
/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode() {} * TreeNode(int val) { this.val = val; } * TreeNode(int val, TreeNode left, TreeNode right) { * this.val = val; * this.left = left; * this.right = right; * } * } */ class Solution { public int longestZigZag(TreeNode root) { if(root==null) { return 0; } return Math.max(1+helper(root.left,'l'),1+helper(root.right,'r')); } public int helper(TreeNode root,char c) { if(root==null) { return -1; } if(c=='l') { return Math.max(1+helper(root.right,'r'),0+helper(root.left,'l')); } else { return Math.max(1+helper(root.left,'l'),0+helper(root.right,'r')); } } }
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