Solution of Inorder Successor and Tree Serialization and Deserialization

Author: Garvit244

200-300q/285.py

@@ -0,0 +1,37 @@
+'''
+Given a binary search tree and a node in it, find the in-order successor of that node in the BST.
+Note: If the given node has no in-order successor in the tree, return null
+'''
+
+# Definition for a binary tree node.
+# class TreeNode(object):
+# def __init__(self, x):
+# self.val = x
+# self.left = None
+# self.right = None
+
+class Solution(object):
+ def inorderSuccessor(self, root, p):
+ """
+ :type root: TreeNode
+ :type p: TreeNode
+ :rtype: TreeNode
+"""
+
+if not root or not p:
+return None
+
+if p.right:
+p = p.right
+while p.left:
+p = p.left
+return p
+
+successor = None
+while root and root != p:
+if root.val > p.val:
+successor = root
+root = root.left
+else:
+root = root.right
+return successor

200-300q/297.py

@@ -0,0 +1,71 @@
+'''
+Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in the same or another computer environment.
+
+Design an algorithm to serialize and deserialize a binary tree. There is no restriction on how your serialization/deserialization algorithm should work. You just need to ensure that a binary tree can be serialized to a string and this string can be deserialized to the original tree structure.
+
+Example: 
+
+You may serialize the following tree:
+
+ 1
+ / \
+ 2 3
+ / \
+ 4 5
+
+as "[1,2,3,null,null,4,5]"
+'''
+
+# Definition for a binary tree node.
+# class TreeNode(object):
+# def __init__(self, x):
+# self.val = x
+# self.left = None
+# self.right = None
+
+class Codec:
+
+ def serialize(self, root):
+ """Encodes a tree to a single string.
+ 
+ :type root: TreeNode
+ :rtype: str
+ """
+ 
+ def preorder(root):
+ if root:
+ seralizeTree.append(str(root.val) + ',')
+ preorder(root.left)
+ preorder(root.right)
+ else:
+ seralizeTree.append('#,')
+ 
+ seralizeTree = []
+ preorder(root)
+ return ''.join(seralizeTree)
+ 
+
+ def deserialize(self, data):
+ """Decodes your encoded data to tree.
+ 
+ :type data: str
+ :rtype: TreeNode
+ """
+ 
+ def buildTree(preorder):
+ value = preorder.pop(0)
+ if value == '#':
+ return None
+ 
+ node = TreeNode(int(value))
+ node.left = buildTree(preorder)
+ node.right = buildTree(preorder)
+ return node
+ 
+ preorder = data.split(',')[:-1]
+ return buildTree(preorder)
+ 
+
+# Your Codec object will be instantiated and called as such:
+# codec = Codec()
+# codec.deserialize(codec.serialize(root))

README.md

@@ -24,9 +24,12 @@ Python solution of problems from [LeetCode](https://leetcode.com/).
 | # | Title | Solution | Difficulty |
 |---| ----- | -------- | ---------- |
 |300|[Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence/) | [Python](./200-300q/300.py)|Medium|
+|297|[Serialize and Deserialize Binary Tree](https://leetcode.com/problems/serialize-and-deserialize-binary-tree) | [Python](./200-300q/297.py)|Hard|
 |295|[Find Median from Data Stream](https://leetcode.com/problems/find-median-from-data-stream/) | [Python](./200-300q/295.py)|Hard|
 |289|[Game of Life](https://leetcode.com/problems/game-of-life) | [Python](/200-300q/289.py)|Medium|
 |287|[Find the Duplicate Number](https://leetcode.com/problems/find-the-duplicate-number/) | [Python](./200-300q/287.py)|Hard|
+|285|[Inorder Successor in BST](https://leetcode.com/problems/inorder-successor-in-bst) | [Python](./200-300q/285.py)|Medium|
+|283|[Move Zeros](https://leetcode.com/problems/move-zeroes)|[Python](./200-300q/283.py)|Easy|
 |279|[Perfect Squares](https://leetcode.com/problems/perfect-squares/) | [Python](./200-300q/279.py)|Medium|
 |268|[Missing Number](https://leetcode.com/problems/missing-number)|[Python](./200-300q/268.py)|Easy|
 |253|[Meeting Rooms II](https://leetcode.com/problems/meeting-rooms-ii) | [Python](./200-300q/253.py)|Medium|