Oulipo POJ - 3461（kmp,求重叠匹配个数）

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 {${}^{\prime }{A}^{\prime }{,}^{\prime }{B}^{\prime }{,}^{\prime }{C}^{\prime },\dots {,}^{\prime }{Z}^{\prime }$}, with $1\le |W|\le 10,000$ (here $|W|$ denotes the length of the string $W$).
One line with the text $T$, a string over {${}^{\prime }{A}^{\prime }{,}^{\prime }{B}^{\prime }{,}^{\prime }{C}^{\prime },\dots {,}^{\prime }{Z}^{\prime }$}, with $|W|\le |T|\le 1,000,000$.

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

题意：

给出$T$组数据，每组数据有两个字符串，让我们查找第一个字符串在第二个字符串中出现的次数，可重叠；

思路：kmp；

注意：使用C++中cin、cout作为输入输出语句将导致超时；

具体代码如下：

#include
#include
#include
using namespace std;
#define maxx 2000100
char a[maxx],b[10100];
int n,m;
int p[maxx];
void pre()
{
    int i=0,j=-1;
    p[0]=-1;
    while(i<m)
    {
        if(j==-1||b[i]==b[j])
        {
            j++,i++;
            p[i]=j;
        }
        else
            j=p[j];
    }
}
void kmp()
{
    int i=0,j=0,ans=0;
    while(i<n)
    {
        if(j==-1||a[i]==b[j])
        {
            i++,j++;
            if(j==m)
            {
                ans++;
                j=p[j];
            }
        }
        else
            j=p[j];
    }
    printf("%d\n",ans);
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%s%s",b,a);
        n=strlen(a);//
        m=strlen(b);
        pre();
        kmp();
    }
    return 0;
}

实践是检验真理的唯一标准
下面再来一个不重叠匹配个数的
剪花布条 HDU - 2087