1 def merge(a, b):
2 c = []
3 h = j = 0
4 while j < len(a) and h < len(b):
5 if a[j] < b[h]:
6 c.append(a[j])
7 j += 1
8 else:
9 c.append(b[h])
10 h += 1
11
12 if j == len(a):
13 for i in b[h:]:
14 c.append(i)
15 else:
16 for i in a[j:]:
17 c.append(i)
18
19 return c
20
21
22 def merge_sort(lists):
23 if len(lists) <= 1:
24 return lists
25 middle = int(len(lists)/2)
26 left = merge_sort(lists[:middle])
27 right = merge_sort(lists[middle:])
28 return merge(left, right)
29
30
31 if __name__ == '__main__':
32 a = [4, 7, 8, 3, 5, 9]
33 print(merge_sort(a))
