HDUOJ -----1686

Oulipo

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 3770    Accepted Submission(s): 1485

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

3

BAPC

BAPC

AZA

AZAZAZA

VERDI

AVERDXIVYERDIAN

 

 

Sample Output

1

3

0

 

kmp   ....经典题

思路清晰，就不多说啦！...

就是求目标串在主串中出现几次，即匹配几次,,.

 

代码：

/*@coder 龚细军*/
#include<iostream>
#include<string>
#include<vector>
using namespace std;

int main()
{
    int t,i,j;
    string pw,ps;
    cin>>t;
    while(t--)
    {
        i=0,j=-1;
        cin>>pw>>ps;   /*pw作为目标串，ps作为主串*/
        int lenpw=pw.length();
        int lenps=ps.length();
        vector<int>next(lenpw+1,0);
        next[i]=-1;
        while(i<lenpw)
        {
            if(j==-1||pw[i]==pw[j])
            {
                ++i;
                ++j;
                if(pw[i]!=pw[j])
                    next[i]=j;
                else
                    next[i]=next[j];
            }
            else
                j=next[j];
        }
        i=-1,j=-1;
        int ans=0;
        while(i<lenps)
        {
            if(j==-1||pw[j]==ps[i])
            {
                ++i;
                ++j;
            }
            else
                j=next[j];
         if(j==lenpw)
             ans++;
        }
        printf("%d\n",ans);
    }
  return 0;
}