python: add problem 12 and unittest

Author: supercoderhawk

Python/sln_1_100/solution_11_20.py

@@ -1,11 +1,48 @@
 # -*- coding: utf-8 -*-
+from collections import OrderedDict
+from typing import List
+
 
 class Solution_11_20(object):
     def intToRoman(self, num):
         """
-
+        12
         :param num:
         :return:
         """
-        rets = ['I','V','X','L','C','D','M']
+        num2roman = {1: 'I', 5: 'V', 10: 'X', 50: 'L', 100: 'C', 500: 'D', 1000: 'M'}
+        rets = ['I', 'V', 'X', 'L', 'C', 'D', 'M']
+        for n in num2roman:
+            num
+
+    def threeSumClosest(self, nums: List[int], target: int) -> int:
+        """
+        16
+        :param nums:
+        :param target:
+        :return:
+        """
+        if len(nums) == 3:
+            return sum(nums)
+        nums = sorted(nums)
+
+        if sum(nums[:3]) >= target:
+            return sum(nums[:3])
+        if sum(nums[-3:]) <= target:
+            return sum(nums[-3:])
+        min_diff = sum(nums[:3])-target
+        for i in range(len(nums) - 2):
+            j = i + 1
+            k = len(nums) - 1
+            while j < k:
+                diff = nums[i] + nums[j] + nums[k] - target
+                if diff < 0:
+                    j += 1
+                elif diff > 0:
+                    k -= 1
+                else:
+                    return target
+                if abs(diff) < abs(min_diff):
+                    min_diff = diff
 
+        return min_diff + target

Python/sln_1_100/test_solution_11_20.py

@@ -0,0 +1,12 @@
+# -*- coding: utf-8 -*-
+from unittest import TestCase
+from sln_1_100.solution_11_20 import Solution_11_20
+
+
+class Test_solution_11_20(TestCase):
+    def setUp(self) -> None:
+        self.sln = Solution_11_20()
+
+    def test_threeSumClosest(self):
+        ret = self.sln.threeSumClosest([-1, 0, 1, 1, 55], 3)
+        self.assertEqual(ret, 2)