poj-3461 Oulipo 【kmp】

Oulipo

Time Limit: 1000MS Memory Limit: 65536KTotal Submissions: 26367 Accepted: 10522

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

3BAPCBAPCAZAAZAZAZAVERDIAVERDXIVYERDIAN

Sample Output

130

Source

BAPC 2006 Qualification

计算字串在母串中出现的次数

#include<stdio.h>#include<iostream>#include<math.h>#include<stdlib.h>#include<ctype.h>#include<algorithm>#include<vector>#include<string.h>#include<queue>#include<stack>#include<set>#include<map>#include<sstream>#include<time.h>#include<malloc.h>using namespace std;char a[100000500], b[10005000];int Next[10005000],ans;void get_next(char b[], int m){int i = 0;Next[0] = -1;int j = -1;while (i<m){if (j == -1 || b[i] == b[j]){++i;++j;if (b[i] == b[j])Next[i] = Next[j];elseNext[i] = j;}elsej = Next[j];}}int KMP(char a[], int n, char b[], int m, int Next[], int pos){int i = pos;int j = 0;while (i<n&&j<m){if (j == -1 || a[i] == b[j]){++i;++j;}elsej = Next[j];if (j == m){ans++;j = Next[j];}}return ans;}int main(){int test, n, m, i, j;scanf("%d", &test);while (test--){scanf("%s%s",a,b);int n = strlen(a);int m = strlen(b);get_next(a, n);ans = 0;KMP(b, m, a, n, Next, 0);printf("%d\n",ans);}}