merge 2 sorted lists with simple tests

sorting/merge2lists.py

@@ -0,0 +1,124 @@
+
+def mergeboth(a, b):
+    index = 0
+    length = len(a) + len(b)
+    c = []
+    if len(a) == 0:
+        print('----- Final result -----')
+        print(b)
+        print('------------------------')
+        return b
+    if len(b) == 0:
+        print('----- Final result -----')
+        print(a)
+        print('------------------------')
+        return a
+    while len(c) < length-1:
+        if a[index] <= b[index]:
+            print(str(a[index]) + ' minor than ' + str(b[index]))
+            if len(c) > 1 and a[index] < c[-1]:
+                c.insert(-1, a[index])
+            else:
+                c.append(a[index])
+            c.append(b[index])
+            print('Current C array')
+            print(c)
+        else:
+            print(str(a[index]) + ' major than ' + str(b[index]))
+            if len(c) > 1 and b[index] < c[-1]:
+                c.insert(-1, b[index])
+            else:
+                c.append(b[index])
+            c.append(a[index])
+            print('Current C array')
+            print(c)
+        if index == len(a) -1:
+            if index < len(b)-1:
+                print('there are elements left from: ' + str(index) )
+                print('elements left from ' + str(index))
+                print(b[index+1:])
+                c.extend(b[index+1:])
+                print('Check lengths')
+                print(length, len(c))
+        else:
+            if index == len(b)-1:
+                print('there are elements left from: ' + str(index) )
+                print('elements left from ' + str(index))
+                print(a[index+1:])
+                c.extend(a[index+1:])
+                print('Check lengths')
+                print(length, len(c))
+            else:
+                index += 1
+    print('----- Final result -----')
+    print(c)
+    print('------------------------')
+    return c
+
+def test1():
+    print('starting test1')
+    a = [1,2,5,8,8]
+    b = [3,6,7,7]
+    assert mergeboth(a, b) == [1, 2, 3, 5, 6, 7, 7, 8, 8]
+    print('------------------------')
+
+
+def test2():
+    print('starting test2')
+    f = [1,4,6,8,9]
+    g = [2,5,7]
+    assert mergeboth(f,g) == [1, 2, 4, 5, 6, 7, 8, 9]
+    print('------------------------')
+
+
+def test3():
+    print('starting test3')
+    d = [2,6,8]
+    e = [1,7,9]
+    assert mergeboth(d,e) == [1, 2, 6, 7, 8, 9]
+    print('------------------------')
+
+def test4():
+    print('starting test4')
+    a = [1,3,5,7]
+    b = [2,4,6]
+    assert mergeboth(a,b) == [1, 2, 3, 4, 5, 6, 7]
+    print('------------------------')
+
+def test5():
+    print('starting test5')
+    a = [1,2,9]
+    b = [5,7,8]
+    assert mergeboth(a,b) == [1, 2, 5, 7, 8, 9]
+    print('------------------------')
+
+def test6():
+    print('starting test6')
+    a = [1,2]
+    b = []
+    assert mergeboth(a,b) == [1, 2]
+    print('------------------------')
+
+def test7():
+    print('starting test7')
+    a = []
+    b = []
+    assert mergeboth(a,b) == []
+    print('------------------------')
+
+def test8():
+    print('starting test8')
+    a = []
+    b = [1,2]
+    assert mergeboth(a,b) == [1, 2]
+    print('------------------------')
+
+if __name__ == "__main__":
+    test1()
+    test2()
+    test3()
+    test4()
+    test5()
+    test6()
+    test7()
+    test8()

sorting/mergesort.py

@@ -0,0 +1,42 @@
+
+
+def merge_sort(original_list):
+    print('entering divide')
+    if len(original_list) > 1:
+        middle_index = len(original_list)//2
+        left = original_list[:middle_index]
+        right = original_list[middle_index:]
+        merge_sort(left)
+        merge_sort(right)
+        print('i am back!')
+        left_index, right_index, original_index = 0, 0, 0
+        while left_index < len(left) and right_index < len(right):
+            if left[left_index] <= right[right_index]:
+                original_list[original_index] = left[left_index]
+                left_index += 1
+            else:
+                original_list[original_index] = right[right_index]
+                right_index += 1
+            original_index += 1
+            print('we have just put two values in order from both halves')
+            print(right[right_index-1], left[left_index-1])
+
+        while left_index < len(left):
+            print('this means that right half is out of stock')
+            print(right, right_index, left, left_index)
+            original_list[original_index] = left[left_index]
+            left_index += 1
+            original_index += 1
+
+        while right_index < len(right):
+            print('this means that left half is out of stock')
+            print(right, right_index, left, left_index)
+            original_list[original_index] = right[right_index]
+            right_index += 1
+            original_index += 1
+
+if __name__ == '__main__':
+    list_to_sort = [5,4,2,7,9,1]
+    merge_sort(list_to_sort)
+    print('now sorted')
+    print(list_to_sort)