HDU 1689 Oulipo 【KMP】

Oulipo

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 5557    Accepted Submission(s): 2222

Problem 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

/*

套用KMP模板

*/

#include<cstdio>
#include<cstring>
#define N 1000002
int next[N];
void getnext(char *p){
    int i=0,len=strlen(p);
    int j=next[0]=-1;
    while(i<len){
        if(j==-1||p[j]==p[i]){
            i++,j++;
            next[i]=j;
        }
        else{
            j=next[j];
        }
    }
}
int kmp(char *s,char *p){
    int i,j,sum,len1=strlen(s),len2=strlen(p);
    i=j=sum=0;
    while(i<len1){
        if(j==-1||s[i]==p[j]){
            i++,j++;
        }
        else j=next[j];
        if(j==len2) {sum++; j=next[j];}
    }
    return sum;
} 
int main(){
     int n;
     char s[N],p[N];
     while(scanf("%d",&n)!=EOF){
        scanf("%s %s",p,s);
        getnext(p);   
        printf("%d\n",kmp(s,p));
    }
    return 0;
}