Oulipo Time Limit: 1000MS Memory Limit: 65536K Total Submissions: 31293 Accepted: 12643
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
#include#include #include #include #include #include #define F(i,j,n) for(int i=j;i<=n;i++) #define maxn 1000100 char s[maxn],p[maxn]; int nxt[maxn],ls,lp,t,ans; inline void getnext() { int i=0,j=-1; nxt[0]=-1; while (i!=lp) { if (j==-1||p[i]==p[j]) nxt[++i]=++j; else j=nxt[j]; } } inline void kmp() { int i=0,j=0;ans=0; while (i!=ls) { if (s[i]==p[j]||j==-1) ++i,++j; else j=nxt[j]; if (j==lp) { ans++; j=nxt[j]; } } } int main() { scanf("%d",&t); while (t--) { scanf("%s%s",p,s); ls=strlen(s);lp=strlen(p); getnext(); kmp(); printf("%d\n",ans); } return 0; }