hdu 1686 Oulipo(KMP)

Oulipo

Time Limit: 3000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)

Total Submission(s): 4490 Accepted Submission(s): 1772


Problem DescriptionThe 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.



InputThe 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.



OutputFor 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 Input3

BAPC

BAPC

AZA

AZAZAZA

VERDI

***ERDXIVYERDIAN

Sample Output

1

3

0

#include<stdio.h>
#include<string.h>
int la,lb,next[10002];
char a[1000002],b[1000002];
void getnext(char s[],int len)
{
	int i,j;
	next[0]=-1;
	i=0;j=-1;
	while(i<len)
	{
		if(j==-1 || s[i]==s[j])
			i++,j++,next[i]=j;
		else j=next[j];
	}
}
int kmp()
{
	int i,j,ans=0;
	i=0;j=0;
	while(i<lb)
	{
		if(j==-1 || a[j]==b[i]) i++,j++;
		else j=next[j];
		if(j>=la){
			ans++;j=next[j];
		}
	}
	return ans;
}
int main()
{
	int i,n;
	scanf("%d",&n);
	while(n--)
	{
		scanf("%s%s",&a,&b);
		la=strlen(a);
		lb=strlen(b);
		getnext(a,la);
		printf("%d\n",kmp());
	}
	return 0;
}