记录贴，互勉

700. Search in a Binary Search Tree
Hint: BST left < root < right

701. Insert into a Binary Search Tree
Compare left and right node value and decide which brunch need to be insert

230. Kth Smallest Element in a BST
In_order

99. Recover Binary Search Tree
(Exactly two nodes of the tree were swapped by mistake)
In this case, we use in order traversal to recursively visit the BST.
Case one: 1 4 3 2 5    4 and 2 need to be swap, in this case node1 is pre, node2 is root
Case two: 1 3 2 4 5   3 and 2 need to be swap, in this case node1 is pre, node2 is root
each case we found a mistake, we need to remember the root to satisfy this two cases

99. Iterative solution

108. Convert Sorted Array to Binary Search Tree
Recursive: mid as root node, split the array as left and right from mid.

501. Find Mode in Binary Search Tree
Solution using map

微信用户_b99d1cc 发表于 2023-9-8 19:28
501. Find Mode in Binary Search Tree
Solution using map

or use in order traversal  to mark the same number of value

450. Delete Node in a BST
Recursive solution:
1. Find the key
2. replace the target key value
3. delete the replaced value's node

133. Clone Graph
1. copy   (Map old to new)
2. connect (From map find the old node's neighbor for new node)