Sort a linked list using insertion sort

Author: don6hao

insertion_sort_list.py

@@ -0,0 +1,76 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+# Definition for singly-linked list.
+class ListNode:
+    def __init__(self, x):
+        self.val = x
+        self.next = None
+
+class Solution:
+    # @param head, a ListNode
+    # @return a ListNode
+    def insertionSortList(self, head):
+        if None == head:
+            return None
+        #记录尾部节点
+        tail_node = head
+        next_node  = head.next
+        while None != next_node:
+            if head.val >= next_node.val:
+                ## 更新头指针和next_node
+                tmp = next_node.next
+                next_node.next = head
+                head = next_node
+                next_node = tmp
+            elif tail_node.val <= next_node.val:
+                #小于或等于尾部节点
+                tail_node.next = next_node
+                tail_node = next_node
+                next_node = next_node.next
+            else:
+                #从头部查找合适位置进行插入操作
+                tmp = head.next
+                prev = head
+                while None != tmp:
+                    if tmp.val > next_node.val:
+                        break;
+                    prev = tmp
+                    tmp = tmp.next
+                prev.next = next_node
+                next_node = next_node.next
+                prev.next.next = tmp
+        tail_next = next_node #None
+        return head
+
+
+if __name__ == "__main__":
+    s = Solution()
+    head = ListNode(4)
+    node_1 = ListNode(1)
+    head.next = node_1
+
+    node_2 = ListNode(3)
+    node_1.next = node_2
+
+    node_3 = ListNode(5)
+    node_2.next = node_3
+
+    node_4 = ListNode(9)
+    node_3.next = node_4
+
+    node_5 = ListNode(2)
+    node_4.next = node_5
+
+    node_6 = ListNode(8)
+    node_5.next = node_6
+
+    node_7 = ListNode(13)
+    node_6.next = node_7
+
+    node = s.insertionSortList(head)
+
+    while None != node:
+        print node.val
+        node = node.next
+
+