86 update

Author: tech-cow

linkedlist/PartitionLinkedList.py

@@ -0,0 +1,31 @@
+# Definition for singly-linked list.
+# Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x.
+# You should preserve the original relative order of the nodes in each of the two partitions.
+# Given 1->4->3->2->5->2 and x = 3,
+# return 1->2->2->4->3->5.
+
+
+#思路
+#设置两个guardnode
+#然后制造两个temp node用于循环
+#将第一个链表的末尾指向第二个的开头，返还第一个guardnode.next
+
+class Solution(object):
+    def partition(self, head, x):
+        small, large = ListNode(0), ListNode(0)
+        cur1, cur2 = small, large
+
+        while head:
+            if head.val < x:
+                cur1.next = head
+                cur1 = cur1.next
+            else:
+                cur2.next = head
+                cur2 = cur2.next
+
+            head = head.next
+
+        cur2.next = None
+        cur1.next = large.next
+
+        return small.next