Binary Tree Good Questions

(1) Verify preorder sequence in Binary Search Tree (leetcode 255)
(2) serialize and deserialize binary Tree (leetcode 297)
(3) Recover binary search tree (leetcode 99)
(4) populating next right pointer in each node (leetcode 117)
(5) Convert common ancestor of binary Tree((236) BST(235)
(6) largest BST substree (leetcode 333)
(7) Kth smallest element in BST(leetcode 230) frequent search with modify( node with size infor)
(8) flatten binary tree to linked list(leetcode 114)
(9) count the complete tree node (leetcode 222) try iterative
(10) construct tree from preorder and inorder traversal (leetcode 105)
(11) closest binary search tree value II (leetcode 272) similar: two sum of BST
(12) Binary Tree upside down (leetcode 156)
(13) Binary Tree postorder traversal (leetcode 145)
(14) Binary Tree maximum path sum (leetcode 124)