add 101

Author: cskenken

code/101.symmetric-tree.103350447.ac.py

@@ -0,0 +1,30 @@
+# Definition for a binary tree node.
+# class TreeNode(object):
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution(object):
+    def isSymmetric(self, root):
+        """
+        :type root: TreeNode
+        :rtype: bool
+        """
+        if root==None:
+            return True
+        else:
+            return self.isSymmetricHelper(root.left,root.right)
+        
+        
+            
+    def isSymmetricHelper(self,node1,node2):
+        if node1==None:
+            return node2==None
+        if node2==None:
+            return node1==None
+        if node1.val==node2.val:
+            return self.isSymmetricHelper(node1.left,node2.right) and self.isSymmetricHelper(node1.right,node2.left)
+        return False
+        
+