B

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

计算模式串在文本串中出现的次数

#include <iostream>#include <cstdio>#include <cstring>#include <cstdlib>#include <algorithm>using namespace std;const int maxn = 1000000;char text[maxn];char pattern[maxn];int nnext[maxn];void get_next(){   int patternLen = strlen(pattern);   nnext[0] = nnext[1] = 0;   for(int i=1;i<patternLen;i++)   {     int j = nnext[i];     while(j&&pattern[i]!=pattern[j])     {       j = nnext[j];     }     nnext[i+1] = pattern[i]==pattern[j]?j+1:0;   }}int kmp(){  int ans = 0;  int textLen = strlen(text);  int patternLen = strlen(pattern);  int j = 0;  for(int i = 0; i < textLen; i++)  {     while(j&&pattern[j]!=text[i])     j = nnext[j];     if(pattern[j]==text[i])     j++;     if(j==patternLen)     ans++;  }  return ans;}int main(){  int T;  scanf("%d", &T);  while(T--)  {    scanf("%s %s", pattern, text);    get_next();    printf("%d\n", kmp());  }  return 0;}