先序遍历和后序遍历

Azureki · Dec 2, 2018 · ec009f7 · ec009f7
1 parent da4f03e
commit ec009f7
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diff --git a/lc144. Binary Tree Preorder Traversal.py b/lc144. Binary Tree Preorder Traversal.py
@@ -0,0 +1,24 @@
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution:
+    def preorderTraversal(self, root):
+        """
+        :type root: TreeNode
+        :rtype: List[int]
+        """
+        def dfs(root):
+            if not root:
+                return
+            res.append(root.val)
+            dfs(root.left)
+            dfs(root.right)
+
+        res=[]
+        dfs(root)
+        return res
+
diff --git a/lc145. Binary Tree Postorder.py b/lc145. Binary Tree Postorder.py
@@ -0,0 +1,24 @@
+# Definition for a binary tree node.
+# class TreeNode:
+#     def __init__(self, x):
+#         self.val = x
+#         self.left = None
+#         self.right = None
+
+class Solution:
+    def postorderTraversal(self, root):
+        """
+        :type root: TreeNode
+        :rtype: List[int]
+        """
+        def dfs(root):
+            if not root:
+                return
+            dfs(root.left)
+            dfs(root.right)
+            res.append(root.val)
+
+        res=[]
+        dfs(root)
+        return res
+