KMP Oulipo

Oulipo

Time Limit : 3000/1000ms (Java/Other)   Memory Limit : 32768/32768K (Java/Other)

Total Submission(s) : 40   Accepted Submission(s) : 26

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

 

Source

華東區大學生程序設計邀請賽_熱身賽

 

例如：用KMP記錄字串與母串比較不相等時字串返回的位置

abcabcab  -1 0 0 0 1 2 3 4

abababab  -1 0 0 1 2 3 4 5

 

#include<stdio.h>
#include<string.h>
#define M 1010000
char a[M],b[M];
int p[M];
int sum,len1,len2;
//P()是字串與字串的比較 
void P()//求得字串與母串比較不相等時，字串返回的位置 
{
	int i,j;
	i=0;j=-1;//規定字串第一個字符爲-1，第二個字符爲0。 
	p[i]=j;
	while(i<len1)
	{
		if(j==-1||a[i]==a[j])
		{
			j++;i++;
			p[i]=j;
		}
		else j=p[j];
	}
}
void kmp()
{
	P();
	int i=0;
	int j=0;
	while(i<len2)
	{
		if(j==-1||a[j]==b[i])
		{
			i++;j++;
			if(j==len1)
			sum++;
		}
		else j=p[j];//每一次比較不相等時字串回到的位置 
	}
}
int main()
{
	int T;
	scanf("%d",&T);
	while(T--)
	{
		scanf("%s%s",a,b);
		len1=strlen(a);
		len2=strlen(b);
		sum=0;
		kmp();
		printf("%d\n",sum);
	}
	return 0;
}