[0203]UPDATE:LC-111BFS

Author: Coder-AndyLee

Diff for: 树/111. 二叉树的最小深度-Easy.md

@@ -25,6 +25,32 @@
 
 
 # Solution
+### 1. BFS 效率更高，但有额外空间复杂度
+```python
+class Solution:
+    def minDepth(self, root: TreeNode) -> int:
+        if not root:
+            return 0
+        queue = [root]
+        depth = 1
+
+        while queue:
+            tmp_length = len(queue)
+
+            for i in range(tmp_length):
+                tmp_node = queue.pop(0)
+                if not tmp_node.left and not tmp_node.right:
+                    return depth
+
+                if tmp_node.left:
+                    queue.append(tmp_node.left)
+                if tmp_node.right:
+                    queue.append(tmp_node.right)
+
+            depth += 1
+```
+
+### 2. DFS
 - 时间复杂度：$O(logn)$
 - 空间复杂度：$O(1)$