21 Update

Author: tech-cow

linkedlist/MergeTwoSortedLists.py

@@ -0,0 +1,31 @@
+# Yu Zhou
+# 21. Merge Two Sorted Lists
+# Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists
+
+
+#思路
+#因为是sorted，只需要设置一个guard_node用来之后的return
+#就可以设置一个新的Linkedlist的Node，然后用来储存
+#比对完了的值，最后返回guard_node.next(跳过第一个dummy node)就行了
+
+class Solution(object):
+    def mergeTwoLists(self, n1, n2):
+        #Edge
+        if not n1 and not n2:
+            return None
+
+        node = guard_node = ListNode(0)
+
+        while n1 and n2:
+            if n1.val <= n2.val:
+                node.next = n1
+                n1 = n1.next
+            else:
+                node.next = n2
+                n2 = n2.next
+            node = node.next
+        #Edge
+        if n1 or n2:
+            node.next = n1 or n2
+
+        return guard_node.next