Oulipo (kmp)

Oulipo

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 26857		Accepted: 10709

Description

The French author Georges Perec (1936–1982) once wrote a book, La disparition, without the letter 'e'. He was a member of the Oulipo group. A quote from the book:

Tout avait Pair normal, mais tout s’affirmait faux. Tout avait Fair normal, d’abord, puis surgissait l’inhumain, l’affolant. Il aurait voulu savoir où s’articulait l’association qui l’unissait au roman : stir son tapis, assaillant à tout instant son imagination, l’intuition d’un tabou, la vision d’un mal obscur, d’un quoi vacant, d’un non-dit : la vision, l’avision d’un oubli commandant tout, où s’abolissait la raison : tout avait l’air normal mais…

Perec would probably have scored high (or rather, low) in the following contest. People are asked to write a perhaps even meaningful text on some subject with as few occurrences of a given “word” as possible. Our task is to provide the jury with a program that counts these occurrences, in order to obtain a ranking of the competitors. These competitors often write very long texts with nonsense meaning; a sequence of 500,000 consecutive'T's is not unusual. And they never use spaces.

So we want to quickly find out how often a word, i.e., a given string, occurs in a text. More formally: given the alphabet {'A', 'B', 'C', …, 'Z'} and two finite strings over that alphabet, a word W and a text T, count the number of occurrences of W in T. All the consecutive characters of W must exactly match consecutive characters of T. Occurrences may overlap.

Input

The first line of the input file contains a single number: the number of test cases to follow. Each test case has the following format:

• One line with the word W, a string over {'A', 'B', 'C', …, 'Z'}, with 1 ≤ |W| ≤ 10,000 (here |W| denotes the length of the string W).
• One line with the text T, a string over {'A', 'B', 'C', …, 'Z'}, with |W| ≤ |T| ≤ 1,000,000.

Output

For every test case in the input file, the output should contain a single number, on a single line: the number of occurrences of the word W in the text T.

Sample Input

3
BAPC
BAPC
AZA
AZAZAZA
VERDI
AVERDXIVYERDIAN

Sample Output

1
3
0

Source

BAPC 2006 Qualification

 #include<cstdio>
 #include<cstring>
 char t[ + ] , s[ + ] ;
 int nxt [ + ] ;
 int T ;
 int lens , lent ;

 void PMT ()
 {
     nxt [] = - ;
     for (int i =  , j = - ; i < lent ; i++) {
         while (j != - && t[i] != t[j + ] ) {
             j = nxt[j] ;
         }
         nxt[i] = t[i] == t[j + ] ? ++ j : j ;
     }
 }

 void kmp ()
 {
     int ret =  ;
     PMT () ;//partial match table
     for (int i =  , j = -  ; i < lens ; i++) {
         while (j != -  && s[i] != t[j + ] ) {
             j = nxt [j] ;
         }
         if (s[i] == t[j + ]) {
             j ++ ;
             if (j == lent - ) {
                 j = nxt [j] ;
                 ret ++ ;
             }
         }
     }
     printf ("%d\n" , ret );
 }

 int main ()
 {
    // freopen ("a.txt" , "r" , stdin ) ;
     scanf ("%d" , &T) ;
     getchar () ;
     while (T--) {
         memset (nxt ,  , sizeof(nxt) ) ;
         gets (t) ;
         gets (s) ;
         lens = strlen (s) ;
         lent = strlen (t) ;
       //  puts (t) , puts (s) ;
         kmp () ;
     }
     return  ;
 }