HDOJ1868Oulipo（KMP算法）

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Oulipo

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

Total Submission(s): 8302    Accepted Submission(s): 3353

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

//大致题意是，给你一个子串和主串，判断在主串中有多少个子串和子串相同，简单的KMP算法

#include<cstdio>
#include<iostream>
#include<cstring>
int len1,len2,count;
char s1[10010],s2[10010*100];
int next[10010];
void Getnext()
{
	int j=-1,i=0;
	next[i]=j;
	while (i<len1)
	{
		if (j==-1||s1[i]==s2[j])
		{
			i++;
			j++;
			next[i]=j;
		}
		else
		j=next[j];
	}
}
void kmp()
{
	Getnext();
	int i=0,j=0;
	while (i<len2)
	{
		if (j==-1||s2[i]==s1[j])
		{
			i++;
			j++;
		}
		else
		j=next[j];
		if (j==len1)
		count++;
	}
}
int main()
{
	int n,i;
	scanf ("%d",&n);
	while (n--)
	{
		scanf ("%s%s",s1,s2);
		len1=strlen(s1);
		len2=strlen(s2);
		count=0;
		kmp();
		printf ("%d\n",count);
	}

}