HDU-1686Oulipo（kmp）

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

题意描述：

找出a串中包含多少个b串

程序代码：

#include<stdio.h>
#include<string.h>
void get_next();
int next[10010],m,n;
char a[1000010],b[10010];
int main()
{int T,i,j,count;scanf("%d",&T);while(T--){scanf("%s%s",b,a);n=strlen(a);m=strlen(b);get_next();i=0;j=0;count=0;while(i<n){if(j==0&&a[i]!=b[j])i++;else if(j>0&&a[i]!=b[j])j=next[j-1];else{i++;j++;}if(j==m){j=next[j-1];count++;}}printf("%d\n",count);}return 0;
}
void get_next()
{int i,j;i=1;j=0;next[0]=0;while(i<m){if(j==0&&b[i]!=b[j]){next[i]=0;i++;}else if(j>0&&b[i]!=b[j])j=next[j-1];else{next[i]=j+1;i++;j++;}}
}