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Author: Chris Wu

problems/n-ary-tree-preorder-traversal.py

@@ -0,0 +1,16 @@
+"""
+Pre-order traversal means that: visit the current node; if there is a left node, visit it; then if there is right node, visit it.
+In-order: Left->Current->Right
+Pre-order: Current->Left->Right
+Post-order: Left->Right->Current
+"""
+class Solution(object):
+    def preorder(self, root):
+        def helper(node):
+            if not node: return
+            opt.append(node.val)
+            for child in node.children:
+                helper(child)
+        opt = []
+        helper(root)
+        return opt