python实现归并排序算法

代码如下:

#!/usr/bin/python
import sys

def merge(array, q, p, r):
left_array = array[q:p+1]
right_array = array[p+1:r+1]

left_array_num = len(left_array)
right_array_num = len(right_array)

i, j , k= [0, 0, q]
while i < left_array_num and j < right_array_num:
if (left_array[i] < right_array[j]):
array[k] = left_array[i]
i+=1
else:
array[k] = right_array[j]
j+=1
k+=1

while i < left_array_num:
array[k] = left_array[i];
k+=1
i+=1

while j < right_array_num:
array[k] = right_array[j]
k+=1
j+=1

def merge_sort(array, q, r):
if q < r:
p = (q + r) / 2
merge_sort(array, q, p)
merge_sort(array, p + 1, r)
merge(array, q, p, r)

if __name__ == "__main__":
array = [2, 45, 5, 7, 34, 456, 345, 89, 8, 1, 341, 4, 98, 67]
merge_sort(array, 0, len(array) - 1)

for a in array:
sys.stdout.write("%d " % a)