298. Binary Tree Longest Consecutive Sequence
298. Binary Tree Longest Consecutive Sequence
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def __init__(self):
self.res = 0
def longestConsecutive(self, root: Optional[TreeNode]) -> int:
def traverse(node, curr):
if not node:
return
if not node.left and not node.right:
if len(curr) == 0:
self.res = max(self.res, 1)
return
if node.val == curr[-1] + 1:
self.res = max(self.res, len(curr) + 1)
else:
self.res = max(self.res, len(curr))
return
if len(curr) == 0:
curr.append(node.val)
else:
if node.val == curr[-1] + 1:
curr.append(node.val)
else:
curr = [node.val]
self.res = max(self.res, len(curr))
traverse(node.left, curr)
traverse(node.right, curr)
curr.pop()
traverse(root, [])
return self.res