HDU 1686 Oulipo

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
   
   
这是一个模板的KMP题 挺基础的
   
   
注意的是 这题要用scanf输入不然会T掉的
   
   


   
   

   
   
#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
using namespace std;
#define MAXN 1000010  
char p[MAXN],s[MAXN];
int f[MAXN];
int ans;
void getnext()
{
	int i,j;
	int len = strlen(p);
	f[0] = 0,f[1] = 0;
	for(i = 1;i<len;i++)
	{
		j = f[i];
		while(j&&p[i]!=p[j])j = f[j];
		f[i+1] = p[i] == p[j]?j+1:0;
	}
	
}

void KMP()
{
	int i,j = 0;
	int len = strlen(s);
	int m = strlen(p);
	for(i = 0;i<len;i++)
	{
		while(j&&p[j]!=s[i])j = f[j];
		if(p[j] == s[i])j++;
		if(j == m){ans++;}
	}
}
int main()
{

	int T;
	cin>>T;
	while(T--)
	{
		ans = 0;
		scanf("%s" , p);  
	    scanf("%s" , s);  
		getnext();
		KMP();
		cout<<ans<<endl;
		
	}
	return 0;
}