python: add problem 40 and unittest

Author: supercoderhawk

Python/sln_1_100/solution_31_40.py

@@ -98,3 +98,29 @@ def recursive_search(self, candidiates, remain_target, target, start_idx, curren
                     current_list.pop()
                 else:
                     break
+
+    def combinationSum2(self, candidates: List[int], target: int) -> List[List[int]]:
+        """
+
+        :param candidates:
+        :param target:
+        :return:
+        """
+        candidates = sorted(candidates)
+        results = []
+        self.recursive_search2(candidates, target, target, 0, [], results)
+        return results
+
+    def recursive_search2(self, candidates, remain_target, target, start_idx, current_list, results):
+        if remain_target == 0:
+            if current_list not in results:
+                results.append(copy.deepcopy(current_list))
+        else:
+            for idx in range(start_idx, len(candidates)):
+                if remain_target - candidates[idx] >= 0:
+                    current_list.append(candidates[idx])
+                    self.recursive_search2(candidates, remain_target - candidates[idx], target,
+                                          idx + 1, current_list, results)
+                    current_list.pop()
+                else:
+                    break

Python/sln_1_100/test_solution_31_40.py

@@ -38,4 +38,8 @@ def test_countAndSay(self):
 
     def test_combinationSum(self):
         ret = self.sln.combinationSum([2, 3, 6, 7], 7)
-        print(ret)
+        assert ret == [[2, 2, 3], [7]]
+
+    def test_combinationSum2(self):
+        ret = self.sln.combinationSum2([10, 1, 2, 7, 6, 1, 5], 8)
+        assert ret == [[1, 1, 6], [1, 2, 5], [1, 7], [2, 6]]