HDU1686——Oulipo

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

 

 

KMP第二弹~

 

 

#include<iostream>

#include<string.h>

#include<stdio.h>

#include<ctype.h>

#include<algorithm>

#include<stack>

#include<queue>

#include<set>

#include<math.h>

#include<vector>

#include<map>

#include<deque>

#include<list>

using namespace std;

char a[1000007],b[10007];

int next[10007];

int c;

int m,n;

void getnext()

{

    int i=0;

    int j=-1;

    next[0]=-1;

    while(i<n)

    {

        if(j==-1||b[j]==b[i])

        {

            i++;

            j++;

            if(b[j]==b[i])

                next[i]=next[j];

            else

                next[i]=j;

        }

        else

            j=next[j];

    }

}



int kmp()

{

    int i=0,j=0;

    while(i<m&&j<n)

    {

        if(j==-1||a[i]==b[j])

        {

            i++;

            j++;

        }

        else

            j=next[j];

        if(j==n)

        {

            j=next[j];

            c++;

        }

    }

    return c;

}

int main()

{

    int test;

    scanf("%d",&test);

    getchar();

    while(test--)

    {

        memset(next,0,sizeof(next));

        c=0;

        gets(b);

        gets(a);

        m=strlen(a);

        n=strlen(b);

        getnext();

        printf("%d\n",kmp());

    }

    return 0;

}