124. Binary Tree Maximum Path Sum
124. Binary Tree Maximum Path Sum
這一題是後序遍歷的經典題目，後序遍歷的精神就是先將子樹的問題全部解決，再開始處理跟節點的問題，這一題要怎麼想到的確是屬於困難的題型。
Postorder Traversal
106. Construct Binary Tree from Inorder and Postorder Traversal
106. Construct Binary Tree from Inorder and Postorder Traversal
postorder
590. N-ary Tree Postorder Traversal
590. N-ary Tree Postorder Traversal
"""
# Definition for a Node.
class
543. Diameter of Binary Tree
543. Diameter of Binary Tree
這一題和 124. Binary Tree Maximum
652. Find Duplicate Subtrees
652. Find Duplicate Subtrees
建議先做過 536. Construct Binary Tree from
114. Flatten Binary Tree to Linked List
114. Flatten Binary Tree to Linked List
這一是後續遍歷很經典的一道題目，體現了後續遍歷很重要的一個精神，當後續遍歷到一半，
145. Binary Tree Postorder Traversal
145. Binary Tree Postorder Traversal
# Definition for a binary tree
337. House Robber III
337. House Robber III
這一題是 198. House Robber 和 213.