| Time Limit: 1000MS | Memory Limit: 65536K | |
| Total Submissions: 23667 | Accepted: 9492 |
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
#include<stdio.h>
#include<string.h>
#include<math.h>
#include<ctype.h>
#include<stdlib.h>
#include<stdbool.h> #define rep(i,a,b) for(i=(a);i<=(b);i++)
#define clr(x,y) memset(x,y,sizeof(x))
#define sqr(x) (x*x)
#define LL long long int i,j,n,num,
f[]; char p[],t[]; int init()
{
clr(p,'\0');
clr(t,'\0');
clr(f,);
num=; scanf("%s",p);
scanf("%s",t); return ;
} void kmp(char *t, char *p, int *f)
{
int n,m,j;
n = strlen(t); m = strlen(p);
getFail(p,f); j = ; for(i = ;i < n;i++) {
while(j && p[j] != t[i]) j=f[j];
if(p[j] == t[i]) j++;
if(j == m) num++;
} } void getFail(char p[],int f[])
{
int m,j,i;
m = strlen(p);
f[] = ;f[] = ; for(i = ;i < m;i++) {
j = f[i];
while(j && p[i] != p[j]) j = f[j];
f[i+]=p[i]==p[j] ? j+ : ;
}
} int main()
{
int T;
scanf("%d",&T); while(T--) {
init();
getFail(p,f);
kmp(t,p,f);
printf("%d\n",num);
}
return ;
}