I have used simple recursion without a helper function. Only 52 cases are passing out of 54. Don't understand why..

```
public int longestConsecutive(TreeNode root) {
if(root == null) return 0;
if(root.left == null && root.right == null) return 1;
int left = 0, right = 0;
if(root.left != null && root.val+1 == root.left.val)
left++;
if(root.right != null && root.val+1 == root.right.val)
right++;
left += longestConsecutive(root.left);
right += longestConsecutive(root.right);
return Math.max(left,right);
}
```