Python使用二分插入排序竟然比直接插入排序快99倍！



Python使用二分插入排序竟然比直接插入排序快99倍！

之前发布同一个算法，C++竟然比C快8倍！  ， 有同学提出是因为C++中使用了二分插入排序，于是用python比较了下两种排序差距有多大。

测试结果如下：

Python insertion sort took time: 1:39:42.448904
Python insertion sort with binary search took time: 0:01:13.263267

代码如下：

import datetime
import bisect

def insertion_sort(l):
    for i in xrange(1, len(l)):
        j = i-1 
        key = l[i]
        while (l[j] > key) and (j >= 0):
           l[j+1] = l[j]
           j -= 1
        l[j+1] = key

def insertion_sort_bin(seq):
    for i in range(1, len(seq)):
        bisect.insort(seq, seq.pop(i), 0, i)

a=[]
for x in range(200000):
	a.append(x)

a.reverse()

start = datetime.datetime.now()
insertion_sort(a)
end = datetime.datetime.now()
print "Python insertion sort took time: %s" % (end-start)

a.reverse()

start2 = datetime.datetime.now()
insertion_sort_bin(a)
end2 = datetime.datetime.now()
print "Python insertion sort with binary search took time: %s" % (end2-start2)

同样是python，算法不一样，速度差百倍！