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
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KMP~
标准模板（？）~
#include<cstdio>
#include<cstring>int n,next[1000000],len1,len2;
char a[10000],s[1000000];void getnext(char *u,int len)
{int k=0;next[1]=0;for(int i=2;i<=len;i++){while(k>0 && u[k+1]!=u[i]) k=next[k];if(u[k+1]==u[i]) k++;next[i]=k;}
}int KMP(char *u,char *v)
{int ans=0;getnext(u,len1);int k=0;for(int i=1;i<=len2;i++){while(k>0 && u[k+1]!=v[i]) k=next[k];if(u[k+1]==v[i]) k++;if(k==len1){ans++;k=next[k];}}return ans;
}int main()
{scanf("%d",&n);while(n--){memset(next,0,sizeof(next));scanf("%s",a+1);scanf("%s",s+1);len1=strlen(a+1),len2=strlen(s+1);printf("%d\n",KMP(a,s));}
}