hdu 1686 Oulipo (KMP裸题)

Oulipo

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 14710    Accepted Submission(s): 5806

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

 

Source

华东区大学生程序设计邀请赛_热身赛

 

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KMP模板题，直接代码。

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;char t[1000005],p[10005];int ne[10005];void makeNext(const char p[],int ne[]){    int len=strlen(p);    ne[0]=0;    for(int i=1,k=0;i<len;i++)    {        while(k>0&&p[i]!=p[k]) k=ne[k-1];        if(p[i]==p[k]) k++;        ne[i]=k;    }}int kmp(const char t[],const char p[],int ne[]){    int n=strlen(t),m=strlen(p),ans=0;    makeNext(p,ne);    for(int i=0,k=0;i<n;i++)    {        while(k>0&&t[i]!=p[k]) k=ne[k-1];        if(t[i]==p[k]) k++;        if(k==m)        {            ans++;        }    }    return ans;}int main(){    int n;    scanf("%d",&n);    while(n--)    {        scanf("%s",p);        scanf("%s",t);        printf("%d\n",kmp(t,p,ne));    }    return 0;}