549. Binary Tree Longest Consecutive Sequence II
https://leetcode.com/problems/binary-tree-longest-consecutive-sequence-ii/
https://github.com/openset/leetcode/tree/master/problems/binary-tree-longest-consecutive-sequence-ii
https://www.lintcode.com/problem/binary-tree-longest-consecutive-sequence-ii/description
Given a binary tree, you need to find the length of Longest Consecutive Path in Binary Tree.
Especially, this path can be either increasing or decreasing. For example, [1,2,3,4] and [4,3,2,1] are both considered valid, but the path [1,2,4,3] is not valid. On the other hand, the path can be in the child-Parent-child order, where not necessarily be parent-child order.
Example 1:
Input: 1 / \ 2 3 Output: 2 Explanation: The longest consecutive path is [1, 2] or [2, 1].
Example 2:
Input: 2 / \ 1 3 Output: 3 Explanation: The longest consecutive path is [1, 2, 3] or [3, 2, 1].
Note: All the values of tree nodes are in the range of [-1e7, 1e7].
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124-binary-tree-maximum-path-sum
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