Python实现的几种排序算法

001

import

sys, getopt, random

002

003

def

bubble_sort(seq):

004

for

i

in

range

(

len

(seq)):

005

for

j

in

range

(

1

,

len

(seq)):

006

if

seq[j

-

1

]>seq[j]:

007

seq[j

-

1

], seq[j]

=

seq[j], seq[j

-

1

]

008

return

seq

009

010

def

insertion_sort(seq):

011

for

i

in

range

(

1

,

len

(seq)):

012

tmp

=

seq[i]

013

pos

=

i;

014

for

j

in

range

(i

-

1

,

-

1

,

-

1

):

015

if

seq[j]>tmp:

016

seq[j

+

1

]

=

seq[j]

017

pos

=

j

018

seq[pos]

=

tmp

019

return

seq

020

021

def

selection_sort(seq):

022

for

i

in

range

(

len

(seq)):

023

min_index

=

i;

024

for

j

in

range

(i,

len

(seq)):

025

if

seq[j]<seq[min_index]:

026

min_index

=

j

027

seq[i],seq[min_index]

=

seq[min_index],seq[i]

028

return

seq

029

030

def

partition(seq,p,l,r):

031

pivot

=

seq[p]

032

seq[p],seq[r]

=

seq[r],seq[p]

033

p_pos

=

l

034

for

i

in

range

(l,r):

035

if

seq[i]<

=

pivot:

036

seq[i],seq[p_pos]

=

seq[p_pos],seq[i]

037

p_pos

=

p_pos

+

1

038

seq[p_pos],seq[r]

=

seq[r],seq[p_pos]

039

return

p_pos

040

041

042

def

quick_sort(seq,left,right):

043

if

left < right:

044

pivot

=

random.randint(left,right)

045

mid

=

partition(seq,pivot,left,right)

046

quick_sort(seq,left,mid

-

1

)

047

quick_sort(seq,mid

+

1

,right)

048

return

seq

049

050

def

shell_sort(seq):

051

incr

=

len

(seq)

/

2

052

while

(incr>

=

1

):

053

for

i

in

range

(incr,

len

(seq)):

054

tmp

=

seq[i]

055

pos

=

i;

056

for

j

in

range

(i

-

incr,

-

1

,

-

incr):

057

if

seq[j]>tmp:

058

seq[j

+

incr]

=

seq[j]

059

pos

=

j

060

seq[pos]

=

tmp

061

incr

=

incr

/

2

062

return

seq

063

064

def

usage():

065

print

'Usage: python sort.py sorttype[-q|-i|-b|-s|--shell]sequence'

066

print

'Example: python sort.py -q 11,32,3,24,5'

067

068

def

main():

069

try

:

070

if

(

len

(sys.argv)

=

=

1

)

or

(

len

(sys.argv)!

=

3

):

071

raise

Exception()

072

else

:

073

opts,args

=

getopt.getopt(sys.argv[

1

:],

'qibs'

,[

'shell'

])

074

075

if

len

(args)>

0

:

076

seq

=

[]

077

tmp

=

args[

0

].split(

','

)

078

for

i

in

tmp:

079

seq.append(

int

(i))

080

else

:

081

raise

Exception()

082

083

for

opt

in

opts:

084

if

opt[

0

]

=

=

'-q'

:

085

print

quick_sort(seq,

0

,

len

(seq)

-

1

)

086

elif

opt[

0

]

=

=

'-i'

:

087

print

insertion_sort(seq)

088

elif

opt[

0

]

=

=

'-b'

:

089

print

bubble_sort(seq)

090

elif

opt[

0

]

=

=

'-s'

:

091

print

selection_sort(seq)

092

elif

opt[

0

]

=

=

'--shell'

:

093

print

shell_sort(seq)

094

095

except

Exception,e:

096

usage()

097

print

e

098

sys.exit()

099

100

if

__name__

=

=

"__main__"

:

101

main()