归并排序算法-python实现

#-*- coding: UTF-8 -*-
import numpy as np

def Merge(a, f, m, l):
i = f
j = m + 1
tmp = []
while i <= m and j <= l:
if a[i] <= a[j]:
tmp.append(a[i])
i += 1
else:
tmp.append(a[j])
j += 1

while i <= m:
tmp.append(a[i])
i += 1
while j<= l:
tmp.append(a[j])
j+= 1
i = f
for x in xrange(0, len(tmp)):
a[i] = tmp[x]
i += 1

def MergeSort(a, f, l):
if f< l:
m = (l + f) / 2
MergeSort(a, f, m)
MergeSort(a, m+1, l)
Merge(a, f, m, l)

if __name__ == '__main__':
a = np.random.randint(0, 10, size = 10)
print "Before sorting..."
print "---------------------------------------------------------------"
print a
print "---------------------------------------------------------------"
MergeSort(a, 0, a.size-1)
print "After sorting..."
print "---------------------------------------------------------------"
print a
print "---------------------------------------------------------------"