Create 297-serialize-and-deserialize.py

Author: stevestar888

297-serialize-and-deserialize.py

@@ -0,0 +1,84 @@
+# 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
+        """
+        if root == None:
+            return []
+        
+        queue = deque()
+        queue.append(root)
+        result = []
+        
+        while queue:
+            item = queue.popleft()
+            
+            if item:
+                result.append(item.val)
+                queue.append(item.left)
+                queue.append(item.right)
+
+            else:
+                result.append("null")
+                
+        print(result)
+        return result
+                
+        
+
+    def deserialize(self, data):
+        """Decodes your encoded data to tree.
+        
+        :type data: str
+        :rtype: TreeNode
+        """
+        self.elem_ptr = 0
+        def get_next_elem():
+            # if self.elem_ptr < len(data) - 1:
+            self.elem_ptr += 1
+            return data[self.elem_ptr]
+        
+        if len(data) == 0:
+            return 
+        
+        root = TreeNode(data[0])
+        
+        queue = deque()
+        queue.append(root)
+        
+        while queue and self.elem_ptr < len(data) - 1:
+            item = queue.popleft()
+            print(item.val)
+            
+            if item: #item exists, so add its children (even if they are null)
+                #add its left child
+                item.left = TreeNode(get_next_elem())
+                
+                #add its right child
+                item.right = TreeNode(get_next_elem())
+                
+                queue.append(item.left)
+                queue.append(item.right)
+
+            else: #item doesn't exist, so no need to children; advance elem_ptr
+                get_next_elem()
+                get_next_elem()
+        
+        return root
+        
+        
+        
+
+# Your Codec object will be instantiated and called as such:
+# codec = Codec()
+# codec.deserialize(codec.serialize(root))