poj3461-Oulipo(KMP)

Oulipo

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 24400		Accepted: 9794

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<iostream>
#include<string.h>
using namespace std;
#define MAXN 1000012


int tcase,next[MAXN];
char s[MAXN],p[MAXN];

int KMP(char p[],char s[]);
void SetNextArray(char p[],int next[]);

int main()
{
    scanf("%d",&tcase);
	getchar();
	while(tcase--)
    {
        gets(p),gets(s);
        printf("%d\n",KMP(p,s));
    }
    return 0;
}

int KMP(char p[],char s[])
{
    SetNextArray(p,next);
    int cnt=0;
    for(int i=0,j=0,ls=strlen(s),lp=strlen(p);ls-i>0;)
    {
        if(j==-1||s[i]==p[j])
        {
            i++;
            j++;
        }
        else j=next[j];
        if(j==lp) cnt++;
    }
    return cnt;
}
void SetNextArray(char p[],int next[])
{
    memset(next,0,sizeof(next)); 
	next[0]=-1;
    for(int i=0,j=-1,l=strlen(p);l-i>0;)
    {
        if(j==-1||p[i]==p[j])
        {
            i++;
            j++;
            next[i]=j;
        }
        else j=next[j];
    }
}