Oulipo（KMP算法）

Oulipo

Time Limit: 1000MS Memory Limit: 65536KTotal Submissions: 31785 Accepted: 12817

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 wordW and a text T, count the number of occurrences of W inT. All the consecutive characters of W must exactly match consecutive characters ofT. 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 stringW).
• 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 wordW in the text T.

Sample Input

3BAPCBAPCAZAAZAZAZAVERDIAVERDXIVYERDIAN

Sample Output

130

#include<iostream>#include<stdio.h>#include<string.h>using namespace std;int sum=0;int next[1000010];char str1[1000010],str2[1000010];void getNext(char *str,int next[]){    int k=strlen(str);    next[0]=-1;    int i=0,j=-1;    while (i<k)    {        if (j==-1||str[i]==str[j])        {            i++;            j++;            next[i]=j;        }        else            j=next[j];    }}void kmp(char *str1,char *str2){    int k=strlen(str1);    int k2=strlen(str2);    getNext(str2,next);    int i=0,j=0;    while (i<k)    {        if (j==-1||str1[i]==str2[j])        {            i++;            j++;            if (j==k2)            {                sum++;                j=next[j];            }        }        else            j=next[j];    }}int main(){    int n;    scanf("%d",&n);    while (n--)    {        sum=0;        scanf("%s%s",str2,str1);        kmp(str1,str2);        printf("%d\n",sum);    }    return 0;}//使用C++中cin、cout作为输入输出语句将导致超时，也是怪坑爹的