hdu 2203(kmp)

 1 /*

 2 *  kmp

 3 */

 4 

 5 #include <cstdio>

 6 #include <cstring>

 7 #include <iostream>

 8 

 9 using namespace std;

10 

11 const int N = 100005;

12 

13 char str[N<<1];

14 char pat[N];

15 int next[N];

16 

17 void indexNext() {

18     int k = 0;

19     next[1] = 0;

20     for (int i=2; pat[i]; ++i) {

21         while (k && pat[k+1]!=pat[i]) k = next[k];

22         if (pat[k+1] == pat[i]) ++k;

23         next[i] = k;

24     }

25 }

26 

27 bool kmp() {

28     int k = 0;

29     int lenPat = strlen(pat) - 1;

30     for (int i=1; str[i]; ++i) {

31         while (k && pat[k+1]!=str[i]) k = next[k];

32         if (pat[k+1] == str[i]) ++k;

33         if (k == lenPat) return true;

34     }

35     return false;

36 }

37 

38 int main() {

39     pat[0] = str[0] = '#';

40     while (scanf("%s%s", str+1, pat+1) != EOF) {

41         int len = strlen(str);

42         if (strlen(pat) > len) {puts("no"); continue;}

43         for (int i=1; i<len; ++i) str[len+i-1] = str[i];

44         str[(len<<1)-1] = '\0'; 

45         indexNext();

46         if (kmp()) puts("yes");

47         else puts("no");

48     }

49     return 0;

50 }