Week 12

Author: 8804who

serialize-and-deserialize-binary-tree/8804who.py

@@ -0,0 +1,68 @@
+from collections import deque
+
+# 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 not root:
+            return ''
+        nodes = []
+        
+        q = deque([[root, 1]])
+
+        while q:
+            node, idx = q.popleft()
+            if not node:
+                continue
+            nodes.append(str(idx)+":"+str(node.val))
+            q.append([node.left, idx*2])
+            q.append([node.right, idx*2+1])
+        
+        return '/'.join(nodes)
+
+
+
+    def deserialize(self, data):
+        """Decodes your encoded data to tree.
+        
+        :type data: str
+        :rtype: TreeNode
+        """
+        if data == '':
+            return None
+
+        data = data.split('/')
+
+        node_dict = {}
+
+        for chunk in data:
+            idx, val = chunk.split(':')
+            node_dict[int(idx)] = val
+
+        def dfs(idx):
+            if idx in node_dict:
+                node = TreeNode(int(node_dict[idx]))
+                node.left = dfs(idx*2)
+                node.right = dfs(idx*2+1)
+                return node
+            else:
+                return None
+
+        return dfs(1)
+
+
+# Your Codec object will be instantiated and called as such:
+# ser = Codec()
+# deser = Codec()
+# ans = deser.deserialize(ser.serialize(root))