Min_Depth_of_Binary_Tree

CodingProgrammer · CodingProgrammer · commit 872114de6d56 · 2017-12-23T12:37:30.000+08:00
diff --git a/111_Minimum_Depth_of_Binary_Tree.py b/111_Minimum_Depth_of_Binary_Tree.py
@@ -0,0 +1,28 @@
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution:
+    def minDepth(self, root):
+        """
+        :type root: TreeNode
+        :rtype: int
+        """
+        if None == root:
+            return 0
+        if None == root.left:
+            return self.minDepth(root.right) + 1
+        if None == root.right:
+            return self.minDepth(root.left) + 1
+        else:
+            return 1 + min(map(self.minDepth, (root.left, root.right))) 
+
+'''
+if root is Null, return 0
+if the left node is Null, return min_depth of the right node and add 1
+if the right node is Null, return min_depth of the left node and add 1
+otherwise, return the min_depth between left_node and right_node and add 1 
+'''
