298.Binary Tree Longest Consecutive Sequence
Given a binary tree, find the length of the longest consecutive sequence path.
The path refers to any sequence of nodes from some starting node to any node in the tree along the parent-child connections.
The longest consecutive path need to be from parent to child (cannot be the reverse).
Longest consecutive sequence path is 3-4-5, so return 3.
Longest consecutive sequence path is 2-3, not 3-2-1, so return 2.
If the left child node exists and the node value is greater than the value of its parent node by 1, the function is called recursively.
If the node value is not exactly greater than 1, the function with the length reset is recursively called. The processing of the right child node and the left child node the same.