POJ 3461 Oulipo

Oulipo

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 16111		Accepted: 6482

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
题目大意：求一个字符串中另一个字符串出现的次数

#include <stdio.h>
#include <string>
#include <string.h>
#include <cstring>
using namespace std;
int arr[1000005];
char str1[1000005];
char str2[1000005];

void getindex(char deststr[], int index[])
{
    int nLen = strlen(deststr);
    int k = -1;
    int j = 0;
    index[0] = -1;
    while(j < nLen)
    {
        if (k == -1 || deststr[k] == deststr[j])
        {
            k++;
            j++;
            index[j] = k;
        }
        else
        {
            k = index[k];
        }
    }
}

int KMP(char srcstr[], char deststr[])
{
    int nLen1 = strlen(srcstr);
    int nLen2 = strlen(deststr);
    getindex(deststr, arr);
    int i = 0;
    int j = 0;
    int nCount = 0;
    while(i < nLen1)
    {
        if (srcstr[i] == deststr[j] || j == -1)
        {
            i++;
            j++;
            if (j == nLen2)
            {
                nCount ++;
            }
        }
        else
        {
            j = arr[j];
        }
    }
    return nCount;
}


int main()
{
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; i++)
    {
        scanf("%s%s", str1, str2);
        printf("%d\n", KMP(str2, str1));
    }
    return 0;
}