mirror of
https://github.com/heqin-zhu/algorithm.git
synced 2024-03-22 13:30:46 +08:00
58 lines
1.5 KiB
Python
58 lines
1.5 KiB
Python
|
''' mbinary
|
||
|
|
#########################################################################
|
||
|
|
# File : sunday.py
|
||
|
|
# Author: mbinary
|
||
|
|
# Mail: zhuheqin1@gmail.com
|
||
|
|
# Blog: https://mbinary.coding.me
|
||
|
|
# Github: https://github.com/mbinary
|
||
|
|
# Created Time: 2018-07-11 15:26
|
||
|
|
# Description: 字符串模式匹配, sunday 算法, kmp 的改进
|
||
|
|
# pattern matching for strings using sunday algorithm
|
||
|
|
#########################################################################
|
||
|
|
'''
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
def getPos(pattern):
|
||
|
|
dic = {}
|
||
|
|
for i,j in enumerate(pattern[::-1]):
|
||
|
|
if j not in dic:
|
||
|
|
dic[j]= i
|
||
|
|
return dic
|
||
|
|
def find(s,p):
|
||
|
|
dic = getPos(p)
|
||
|
|
ps = pp = 0
|
||
|
|
ns = len(s)
|
||
|
|
np = len(p)
|
||
|
|
while ps<ns and pp<np:
|
||
|
|
if s[ps] == p[pp]:
|
||
|
|
ps,pp = ps+1,pp+1
|
||
|
|
else:
|
||
|
|
idx = ps-pp+np
|
||
|
|
if idx >=ns:return -1
|
||
|
|
ch = s[idx]
|
||
|
|
if ch in dic:
|
||
|
|
ps += dic[ch]+1-pp
|
||
|
|
else:
|
||
|
|
ps += np-pp
|
||
|
|
pp = 0
|
||
|
|
if pp==np:return ps-np
|
||
|
|
else:
|
||
|
|
return -1
|
||
|
|
def test():
|
||
|
|
s = [randint(78,88) for i in range(30)]
|
||
|
|
p = [randint(78,88) for i in range(3)]
|
||
|
|
str_s = ''.join((chr(i) for i in s))
|
||
|
|
str_p = ''.join((chr(i) for i in p))
|
||
|
|
n1 = find(s,p)
|
||
|
|
n2 = str_s.find(str_p)
|
||
|
|
if n1!=n2:
|
||
|
|
print(n1,n2,str_p,str_s)
|
||
|
|
return False
|
||
|
|
return True
|
||
|
|
if __name__ =='__main__':
|
||
|
|
from random import randint
|
||
|
|
n = 10000
|
||
|
|
suc = sum(test() for i in range(n))
|
||
|
|
print(f'test {n} times, success {suc} times')
|