poj3461之kmp入门

Oulipo

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 16559		Accepted: 6624

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
***ERDXIVYERDIAN

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
#include<queue>
#include<algorithm>
#include<map>
#include<iomanip>
#define INF 99999999
using namespace std;

const int MAX=10000+10;
char a[MAX],b[1000000];
int next[MAX];

void get_next(char *a){
	int i=-1,j=0,len=strlen(a);
	next[0]=-1;
	while(j<len){
		if(i == -1 || a[i] == a[j]){
			if(a[++i] == a[++j])next[j]=next[j];
			else next[j]=i;
		}else i=next[i];
	}
	return;
}

int KMP(char *a,char *b){
	get_next(a);
	int i=0,j=0,num=0,lena=strlen(a),lenb=strlen(b);
	b[lenb]='#';
	while(j<=lenb){//不需要i<lena,要把b全部比较完 
		if(i == -1 || a[i] == b[j])++i,++j;
		else{//
			if(i == lena)++num;//表示有一个a 
			i=next[i];
		}
	}
	return num;
}

int main(){
	int n;
	cin>>n;
	while(n--){
		cin>>a>>b;
		cout<<KMP(a,b)<<endl;
	}
	return 0;
}