Update code style for Python

codes/python/modules/binary_tree.py

@@ -0,0 +1,76 @@
+"""
+File: binary_tree.py
+Created Time: 2021-12-11
+Author: Krahets (krahets@163.com)
+"""
+
+import collections
+
+class TreeNode:
+    """Definition for a binary tree node
+    """    
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val      # 结点值
+        self.height = 0     # 结点高度
+        self.left = left    # 左子结点引用
+        self.right = right  # 右子结点引用
+
+    def __str__(self):
+        val = self.val
+        left_node_val = self.left.val if self.left else None
+        right_node_val = self.right.val if self.right else None
+        return "<TreeNode: {}, leftTreeNode: {}, rightTreeNode: {}>".format(val, left_node_val, right_node_val)
+
+    __repr__ = __str__
+
+
+def list_to_tree(arr):
+    """Generate a binary tree with a list
+    """
+    if not arr:
+        return None
+    
+    i = 0
+    root = TreeNode(arr[0])
+    queue = collections.deque([root])
+    while queue:
+        node = queue.popleft()
+        i += 1
+        if i >= len(arr): break
+        if arr[i] != None:
+            node.left = TreeNode(arr[i])
+            queue.append(node.left)
+        i += 1
+        if i >= len(arr): break
+        if arr[i] != None:
+            node.right = TreeNode(arr[i])
+            queue.append(node.right)
+            
+    return root
+
+def tree_to_list(root):
+    """Serialize a tree into an array
+    """    
+    if not root: return []
+    queue = collections.deque()
+    queue.append(root)
+    res = []
+    while queue:
+        node = queue.popleft()
+        if node:
+            res.append(node.val)
+            queue.append(node.left)
+            queue.append(node.right)
+        else: res.append(None)
+    return res
+
+def get_tree_node(root, val):
+    """Get a tree node with specific value in a binary tree
+    """    
+    if not root:
+        return
+    if root.val == val:
+        return root
+    left = get_tree_node(root.left, val)
+    right = get_tree_node(root.right, val)
+    return left if left else right