python: add problem 75 and unittest

Author: supercoderhawk

Python/sln_1_100/solution_71_80.py

@@ -81,6 +81,27 @@ def binary_search(func, l):
             return True
         return False
 
+    def sortColors(self, nums: List[int]) -> None:
+        """
+        75
+        Do not return anything, modify nums in-place instead.
+        """
+        prefix_idx = 0
+        suffix_idx = len(nums) - 1
+        idx = 0
+        while idx <= suffix_idx:
+            num = nums[idx]
+
+            if num == 0 and idx > prefix_idx:
+                nums[prefix_idx], nums[idx] = nums[idx], nums[prefix_idx]
+                prefix_idx += 1
+                idx -= 1
+            elif num == 2 and idx < suffix_idx:
+                nums[suffix_idx], nums[idx] = nums[idx], nums[suffix_idx]
+                suffix_idx -= 1
+                idx -= 1
+            idx += 1
+
     def combine(self, n: int, k: int) -> List[List[int]]:
         """
         77

Python/sln_1_100/test_solution_71_80.py

@@ -36,3 +36,11 @@ def test_search_martrix(self):
     def test_combine(self):
         ret = self.sln.combine(4, 2)
         self.assertEqual(ret, [[1, 2], [1, 3], [1, 4], [2, 3], [2, 4], [3, 4]])
+
+    def test_sortColors(self):
+        arr = [2, 0, 2, 1, 1, 0]
+        self.sln.sortColors(arr)
+        assert arr == [0, 0, 1, 1, 2, 2]
+        arr1 = [2, 0, 1]
+        self.sln.sortColors(arr1)
+        assert arr1 == [0, 1, 2]