BF算法

 1 #!/usr/bin/env python
 2 #-*- coding: utf-8 -*-
 3 import sys
 4 
 5 reload(sys)
 6 sys.setdefaultencoding(‘utf-8‘)
 7 
 8 
 9 class PatternMatching(object):
10 
11     def brute_force(self, str_s, str_t):
12         """BF算法
13         """
14         base = 0
15         len_s = len(str_s)
16         len_t = len(str_t)
17 
18         while base + len_t <= len_s:
19             step = 0
20             while step < len_t:
21                 if str_t[step] == str_s[base + step]:
22                     step += 1
23                     continue
24                 base += 1
25                 break
26             if step == len_t:
27                 return base
28         return -1
29 
30 
31 if __name__ == ‘__main__‘:
32     str_s = "ababcabcaabab"
33     str_t = "ababd"
34     calc = PatternMatching()
35     print calc.brute_force(str_s, str_t)