python: add problem 86 and unittest

Author: supercoderhawk

Python/sln_1_100/solution_81_90.py

@@ -0,0 +1,39 @@
+# -*- coding: utf-8 -*-
+from common_utils import ListNode
+
+
+class Solution_81_90(object):
+    def partition(self, head: ListNode, x: int) -> ListNode:
+        """
+        86
+        :param head:
+        :param x:
+        :return:
+        """
+        if not head:
+            return head
+        less_head = less_node = None
+        equal_more_than_head = equal_more_than_node = None
+        node = head
+        while node:
+            val = node.val
+            if val < x:
+                if less_head is None:
+                    less_head = less_node = ListNode(val)
+                else:
+                    less_node.next = ListNode(val)
+                    less_node = less_node.next
+            else:
+                if equal_more_than_head is None:
+                    equal_more_than_head = equal_more_than_node = ListNode(val)
+                else:
+                    equal_more_than_node.next = ListNode(val)
+                    equal_more_than_node = equal_more_than_node.next
+            node = node.next
+
+        if less_head is None:
+            new_head = equal_more_than_head
+        else:
+            less_node.next = equal_more_than_head
+            new_head = less_head
+        return new_head

Python/sln_1_100/test_solution_81_90.py

@@ -0,0 +1,15 @@
+# -*- coding: utf-8 -*-
+from unittest import TestCase
+from sln_1_100.solution_81_90 import *
+from common_utils import *
+
+class Test_Solution_81_90(TestCase):
+    def setUp(self) -> None:
+        self.sln = Solution_81_90()
+
+
+
+    def test_partition(self):
+        head = build_linked_list([1,4,3,2,5,2])
+        ret = self.sln.partition(head,3)
+        print_linked_list(ret)