Leetcode OJ : Implement strStr() [ Boyer–Moore string search algorithm ] python solution

 1 class Solution {

 2 public:

 3 int strStr(char *haystack, char *needle) {

 4     

 5     int i = 0 , skip[256];

 6     char *str = haystack, *substr = needle;

 7     int len_src = strlen(str), len_sub = strlen(substr);

 8     // preprocess

 9     for (i = 0; i < 256; i++)

10         skip[i] = len_sub;

11     int last = len_sub - 1;

12     for (i = 0; i < last;i++)

13         skip[substr[i]] = last - i;

14     // search

15     int pos = 0,  j;

16     while (pos <= len_src-len_sub)  {

17         j = last;

18         while (j>=0 && str[pos+j]==substr[j])

19             j--;

20         if (j<0) 

21              return pos;

22         pos += skip[str[pos+last]];

23     }

24     return -1;

25 }

26 };