HDU 1686 Oulipo

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

3BAPCBAPCAZAAZAZAZAVERDIAVERDXIVYERDIAN

Sample Output

130
题目大意，看样例都懂...
就是匹配串，顺着主串滑动，求匹配次数...
#include<stdio.h>#include<string.h>#include<iostream>using namespace std;char a[1000010];char b[10010];int next[10010];int alen;int blen;void get_next(){    int i=1;    int j=0;    next[1]=0;    while(i<=blen)           //这个i==len  注意。。。    {        /*如果i<len (AZA)                       (AZA)Z(AZA) 匹配数为2          而i<=len  (AZA)                    (AZ(A)Z(A)ZA) 匹配数为3                     仔细看看。。。         */        if(j==0||b[i]==b[j])        {            ++ i;            ++ j;            next[i]=j;          }        else            j=next[j];    }}void KMP(){    int count=0;    int i=1;    int j=1;    while(i<=alen&&j<=blen)    {        if(j==0||a[i]==b[j])        {            ++ i;            ++ j;        }        else        j=next[j];        if(j>blen)        {             count++;             j=next[j];     //匹配成功后，挪到next[j]位置        }    }    printf("%d\n",count);}int main(){    int n;    scanf("%d",&n);    while(n--)    {        scanf("%s%s",b+1,a+1);        alen=strlen(a+1);        blen=strlen(b+1);        get_next();        KMP();    }    return 0;}