【字符串匹配】Oulipo

Oulipo

Time Limit: 1000MS Memory Limit: 65536KTotal Submissions: 13672 Accepted: 5499

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 wordW and a text T, count the number of occurrences of W inT. All the consecutive characters of W must exactly match consecutive characters ofT. 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 stringW).
• 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 wordW in the text T.

Sample Input

3BAPCBAPCAZAAZAZAZAVERDIAVERDXIVYERDIAN

Sample Output

130

Source

BAPC 2006 Qualification

我们要找到所有的匹配，所以匹配成功之后继续匹配下去就行了。j = next[j];

#include <cstdio>#include <cstring>#include <string>char a[10010];char b[1000010];long next[10010];long ans = 0;void get_next(char* str){long j = 1;long k = 0;long len = strlen(a+1);while (j < len+1){if (k==0||str[j]==str[k]){k ++;j ++;next[j] = k;}else k = next[k];}}void kmp(char* str1,char* str2){get_next(str2);long l1 = strlen(str1+1);long l2 = strlen(str2+1);long i = 1;long j = 1;while (i<l1+1 && j<l2+1){if (j==0||str1[i]==str2[j]){i ++;j ++;}else j = next[j];if (j > l2){ans ++;j = next[j];}}}int main(){freopen("oulipo.in","r",stdin);freopen("oulipo.out","w",stdout);long n;scanf("%ld",&n);for (long i=1;i<n+1;i++){memset(next,0,sizeof next);ans = 0;scanf("%s%s",a+1,b+1);kmp(b,a);printf("%ld\n",ans);}return 0;}