HDoj 1686 Oulipo【1つの列が別の列に現れる回数を求めます】【KMP】

3906 ワード

Oulipo
Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 7117    Accepted Submission(s): 2828
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

   
   
   
   
1 3 0

 
标题:あなたに1つの串Pをあげて、1つの串T、PのTの中の出現回数を聞きます.
KMP裸問題:hdojの上のカット布とは違うことに注意してください.
#include <cstdio>
#include <cstring>
#include <algorithm>
#define MAXN 1000000+10
#define LL long long
using namespace std;
char P[MAXN], T[MAXN];
int f[MAXN];
void getfail()
{
    int len = strlen(P);
    f[0] = f[1] = 0;
    for(int i = 1; i < len; i++)
    {
        int j = f[i];
        while(j && P[i] != P[j])
            j = f[j];
        f[i+1] = P[i]==P[j] ? j + 1 : 0;
    }
}
void find()
{
    int m = strlen(P);
    int n = strlen(T);
    int i, j = 0;
    LL ans = 0;
    for(i = 0; i < n; i++)
    {
        while(j && T[i] != P[j])
            j = f[j];
        if(T[i] == P[j])
            j++;
        if(j >= m)
        {
            ans++;
            j = f[j];//              
            //i = i- m + 2;
            //printf("%d
", i); } } printf("%lld
", ans); } int main() { int t; scanf("%d", &t); while(t--) { scanf("%s%s", P, T); getfail(); find(); } return 0; }