LeetCode- Binary Tree Longest Consecutive Sequence

 1 /**
 2  * Definition for a binary tree node.
 3  * public class TreeNode {
 4  *     int val;
 5  *     TreeNode left;
 6  *     TreeNode right;
 7  *     TreeNode(int x) { val = x; }
 8  * }
 9  */
10 public class Solution {
11     public class ConsLen {
12         int fromMe;
13         int fromBelow;
14 
15         public ConsLen(int m, int b){
16             fromMe = m;
17             fromBelow = b;
18         }
19     }
20 
21     public int longestConsecutive(TreeNode root) {
22         if (root==null) return 0;
23             
24         ConsLen res = findConsecutiveSeq(root);
25 
26         return Math.max(res.fromMe,res.fromBelow);
27     }
28 
29     public ConsLen findConsecutiveSeq(TreeNode cur){
30         if (cur.left==null && cur.right==null){
31             return new ConsLen(1,0);
32         }
33 
34         ConsLen res = new ConsLen(1,0);
35         if (cur.left!=null){
36             ConsLen leftRes = findConsecutiveSeq(cur.left);
37             if (cur.left.val == cur.val+1){
38                 res.fromMe = leftRes.fromMe + 1;
39             }
40             res.fromBelow = Math.max(leftRes.fromMe, leftRes.fromBelow);
41         }
42 
43         if (cur.right!=null){
44             ConsLen rightRes = findConsecutiveSeq(cur.right);
45             if (cur.right.val == cur.val+1){
46                 res.fromMe = Math.max(res.fromMe,rightRes.fromMe+1);
47             }    
48             res.fromBelow = Math.max(res.fromBelow,Math.max(rightRes.fromMe,rightRes.fromBelow));
49         }
50         
51         return res;
52     }
53 }