[leetcode]Binary Tree Longest Consecutive Sequence

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/** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ public class Solution { public int longestConsecutive(TreeNode root) { if (root == null) return 0; return Math.max(recurLongest(root.left, root.val, 1), recurLongest(root.right, root.val, 1)); } private int recurLongest(TreeNode root, int parentVal, int lengthSoFar){ if (root == null) return lengthSoFar; if (root.val == parentVal+1) return Math.max(recurLongest(root.left, root.val, lengthSoFar+1), recurLongest(root.right, root.val, lengthSoFar+1)); int rec = Math.max(recurLongest(root.left, root.val, 1), recurLongest(root.right, root.val, 1)); return Math.max(lengthSoFar, rec); } }