Finishes implementing merge sort. Some more tests to be made before switching to something else

03_MergeSort/ms.py

@@ -7,7 +7,7 @@ Implementation of the MergeSort algorithm
 
 class TableSorter():
     """
-    A utili=ty that provides way to sort arrays of elements.
+    A utility that provides a way to sort arrays of elements.
     It should be possible to compare elements to each others
     (meaning a > b and a == b should make sense).
     """
@@ -23,9 +23,38 @@ class TableSorter():
         """
         if len(table) < 1:
             return None
+        elif len(table) == 1:
+            return table
 
         if idx_max == None:
             idx_max = len(table)
 
-        #TODO: Implement
-        return None
+        t_1 = self.mergeSort(table[:len(table)/2])
+        t_2 = self.mergeSort(table[len(table)/2:])
+
+        return self._merge(t_1, t_2)
+
+    def _merge(self, t_1, t_2):
+        """
+        Returns a sorted array t being the concatenation of values from t_1 and t_2.
+        t_1 and t_2 are expected to be sorted themselves.
+        """
+        t = []
+
+        while(t_1 != [] or t_2 != []):
+            if(t_1 == []):
+                t.append(t_2.pop(0))
+            elif(t_2 == []):
+                t.append(t_1.pop(0))
+            else:
+                if(t_1[0] < t_2[0]):
+                    t.append(t_1.pop(0))
+                else:
+                    t.append(t_2.pop(0))
+
+        return t
+
+if __name__ == "__main__":
+        table = [1, 2, 3, 4]
+        sorter = TableSorter()
+        sorter.mergeSort(table)

03_MergeSort/ms_test.py

@@ -10,13 +10,39 @@ import unittest
 
 class test_table_sorter(unittest.TestCase):
 
-    #TODO: Implement
+    def test_merge(self):
+        table = [1, 2]
+        t_1 = [1]
+        t_2 = [2]
+
+        sorter = TableSorter()
+        self.assertEqual(table, sorter._merge(t_1, t_2))
+
+        t_1 = [2]
+        t_2 = [1]
+        self.assertEqual(table, sorter._merge(t_1, t_2))
+
+        table = [1, 2, 3, 5]
+        t_1 = [2, 5]
+        t_2 = [1, 3]
+        self.assertEqual(table, sorter._merge(t_1, t_2))
+
+        t_1 = [3, 5]
+        t_2 = [1, 2]
+        self.assertEqual(table, sorter._merge(t_1, t_2))
+
     def test_mergeSort(self):
 
-        table = [1]
+        table = []
         sorter = TableSorter()
         self.assertEqual(None, sorter.mergeSort(table))
 
+        table = [1]
+        self.assertEqual(table, sorter.mergeSort(table))
+
+        table = [1, 2]
+        self.assertEqual(table, sorter.mergeSort(table))
+
 
 if __name__ == "__main__":
     unittest.main()