Oulipo
Time Limit: 3000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 4490 Accepted Submission(s): 1772
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 子串出现次数,子串可重叠 字母型
#include <stdio.h>
#include <string.h>
#define N 10002 //子链长度
#define M 1000002 //母链长度
char a[M], b[N];
int Next[N];
void getNext(char s[], int len)
{
int i, j;
i = 0; j = -1;
Next[0] = -1;
while (i < len)
{
if (j == -1 || s[i] == s[j])
++i, ++j, Next[i] = j;
else
j = Next[j];
}
}
int KMP(const char a[], const char b[], int pos, int next[], int la, int lb)
{
int i, j;
i = pos, j = 0;
next[0] = -1;
int ans=0;
while (i < la)
{
if (j == -1 || a[i] == b[j])
++i, ++j;
else
j = next[j];
if (j >= lb)
{
ans++;
j=next[j]; //如果不能子链重合 这边要改成j=0;
}
}
return ans;
}
int main()
{
int t;
scanf("%d", &t);
while (t--)
{
scanf("%s", b);//子链
scanf("%s", a);//母链
getNext(b , strlen(b));
printf("%d\n", KMP(a, b, 0, Next, strlen(a), strlen(b)));
}
return 0;
}