feat: balanced-binary-tree

Author: junbinding

Diff for: bt.balanced-binary-tree.py

@@ -0,0 +1,31 @@
+# Definition for a binary tree node.
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+class Solution:
+    """
+    110. 平衡二叉树
+    https://leetcode-cn.com/problems/balanced-binary-tree/
+    给定一个二叉树，判断它是否是高度平衡的二叉树。
+    本题中，一棵高度平衡二叉树定义为：一个二叉树每个节点 的左右两个子树的高度差的绝对值不超过 1 。
+    """
+    def isBalanced(self, root: TreeNode) -> bool:
+        if not root:
+            return True
+
+        if not self.isBalanced(root.left) or not self.isBalanced(root.right):
+            return False
+
+        left = self.maxDepth(root.left) + 1
+        right = self.maxDepth(root.right) + 1
+        return abs(left - right) <= 1
+
+    # 查询节点的最大深度
+    def maxDepth(self, root):
+        if not root:
+            return 0
+
+        return max(self.maxDepth(root.left), self.maxDepth(root.right)) + 1