poj-3461-kmp模板题。。。

Oulipo

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 46290		Accepted: 18452

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

BAPC 2006 Qualification

 

  　　好久没写字符串都要忘了。。所幸还是花几分钟推出来了= =算是写的比以前简洁了吧。f[i]表示i处失配后转移去的位置。

 #include<iostream>
 #include<cstdio>
 #include<cstring>
 #include<vector>
 using namespace std;
 #define inf 0x3f3f3f3f
 int f[];
 char W[];
 char T[];
 int main()
 {
     int n,i,j,k,u,v;
     int t;
     cin>>t;
     while(t--){
         scanf("%s%s",W,T);
         int n1=strlen(W),n2=strlen(T);
         f[]=-;
         for(i=;i<=n1;++i){
             j=f[i-];
             while(j!=-&&W[j]!=W[i-]) j=f[j];
              f[i]=j+;
         }
         int ans=;
         for(i=,j=;i<n2;++i){
             while(j!=-&&W[j]!=T[i]) j=f[j];
             if(j==n1-) ans++;
             j++;
         }
         cout<<ans<<endl;
     }
     return ;
 }