Oulipo
Time Limit: 3000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 4023 Accepted Submission(s): 1591
Problem 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
KMP模板题.
代码:
#include <stdio.h>
#include <string.h>
const int N = 1000005;
const int M = 10005;
char T[N], W[M];
int next[M], t;
void get_next(char *seq, int m) {
next[0] = -1;
int j = next[0];
for (int i = 1; i < m; i++) {
while (j >= 0 && seq[i] != seq[j + 1]) j = next[j];
if (seq[i] == seq[j + 1]) j++;
next[i] = j;
}
}
int kmp(char *seq, char *seq1, int n, int m) {
int j = next[0], ans = 0;
for (int i = 0; i < n; i++) {
while (j >= 0 && seq[i] != seq1[j + 1]) j = next[j];
if (seq[i] == seq1[j + 1]) j++;
if (j == m - 1) {
ans++;
j = next[j];
}
}
return ans;
}
int main() {
scanf("%d", &t);
while (t--) {
scanf("%s%s", W, T);
get_next(W, strlen(W));
printf("%d\n", kmp(T, W, strlen(T), strlen(W)));
}
return 0;
}