HDU - 1686 Oulipo

Oulipo

Time Limit: 1000MS

Memory Limit: 32768KB

64bit IO Format: %I64d & %I64u

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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
    

 

Source

华东区大学生程序设计邀请赛_热身赛

kmp处理字符串，输出匹配数，简单的模板题：

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int maxn=1000000+10;
const int maxm=10000+10;
int next[maxm];
char p[maxm],s[maxn];
int n,m;
void getnext(char *p)//kmp不仅出现在kmp函数，在其他函数也都用到了kmp
{
    int j=-1,i=0;
    next[0]=-1;
    while(i<m)
    {
        if(j==-1||p[i]==p[j])
        {
            i++,j++;
            next[i]=j;
        }
        //else j=next[j];
        else j=-1;//还是这句简洁高效
    }
}


int kmp(char *p,char *s)
{
    int j=0,i=0,c=0;
    while(i<n)
    {
        if(j==-1||s[i]==p[j])
        {
            i++,j++;
        }
        else j=next[j];
        if(j==m)
        {
            c++;
            //j=0;
            //i=i-j-1;
            j=next[j];//如果j==m，按照kmp的思想，使第next[j]位对齐
        }
    }
    //if(j==m) return i-j+1;
    //else return -1;
    return c;
}


int main()
{
    int i,j,t;
    scanf("%d",&t);
    while(t--)
    {
      //scanf("%d%d",&n,&m);
     // for(i=0;i<n;i++)
      scanf("%s",p);
      //for(j=0;j<m;j++)
      scanf("%s",s);
      m=strlen(p);
      n=strlen(s);
      getnext(p);
      printf("%d\n",kmp(p,s));
    }
}