poj3461-Oulipo

Oulipo

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 16965		Accepted: 6821

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

地址：http://poj.org/problem?id=3461

KMP基础，a字符串在b中出现了多少次，最基础的，自己还不会打。。。。。。套的学长给的模板

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <vector>
#include <queue>
#include <algorithm>

using namespace std;
char B[10010],A[1000010];
int next[1000010];
int kmp() {
    int j = -1, ret = 0;
    for (int i = 0; A[i]; i++) {
        while (j != -1 && A[i] != B[j + 1]) j = next[j];
        if (A[i] == B[j + 1]) j++;
        if (!B[j + 1]) {
            ret++;
            j = next[j];
        }
    }
    return ret;
}
void prekmp() {
    next[0] = -1;
    int j = -1;
    for (int i = 1; B[i]; i++) {
        while (j != -1 && B[i] != B[j + 1])
            j = next[j];
        if (B[i] == B[j + 1]) j++;
        next[i] = j;
    }
}


int main()
{
    int n;
    scanf("%d",&n);
    while(n--)
    {
        scanf("%s\n%s",B,A);
        prekmp();
        printf("%d\n",kmp());
    }
    return 0;
}