算法 排序 python 实现--归并排序

理论不多说：

#!/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)