399. Binary Tree Longest Consecutive Sequence

Given the root of a binary tree, return the length of the longest consecutive sequence path.

A consecutive sequence path is a path where the values increase by one along the path.

Note that the path can start at any node in the tree, and you cannot go from a node to its parent in the path.

Example 1:

Input: root = [1,null,3,2,4,null,null,null,5]

Output: 3

Explanation: Longest consecutive sequence path is 3-4-5, so return 3.

Example 2:

Input: root = [2,null,3,2,null,1]

Output: 2

Explanation: Longest consecutive sequence path is 2-3, not 3-2-1, so return 2.

Now Your Turn!

Pick the correct output for the given input

Input: root = [1,2,null,6661,null,6662,null,null,null]

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Constraints:

  • The number of nodes in the tree is in the range [1, 3 * 104].
  • -3 * 104 <= Node.val <= 3 * 104

Hints

Frequently Occurring Doubts

Interview Follow-up Questions

0
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
class Solution {
public:
int longestConsecutive(TreeNode* root) {
// Your code goes here
}
};
Test Case

Input:

Root
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