hdoj 1686 Oulipo

Oulipo

Time Limit: 3000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 7450 Accepted Submission(s): 2998

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
这题几乎是裸裸的KMP ，只是在其基础上，将长串与短串进行处理，找出短串在长串上出现的次数！！
话不多说，上代码！

#include<stdio.h>
#include<string.h>
#define len 1001000
char str[len],ch[len];
int p[len],ans=0,len1,len2;
void Getp()
{
    int i=0,j=-1;
    p[i]=j;
    while(i<len2)
    {
        if(j==-1||str[i]==str[j])//求出next数组(我用的p数组)！ 
        {
            i++,j++;
            p[i]=j;
        }
        else
        j=p[j];
    }
}
void KMP()
{
    Getp();
    int i=0,j=0;
    while(i<len1)
    {
        if(j==-1||str[i]==ch[j])
        {
            i++,j++;
            if(j==len2)
            ans++;//统计短串在长串上出现的次数 
        }
        else
        j=p[j];
    }
}
int main()
{
int n;
scanf("%d",&n);
while(n--)
{
    ans=0;
    scanf("%s%s",ch,str);
     len1=strlen(str);
     len2=strlen(ch);
    KMP();
    printf("%d\n",ans);
}   
    return 0;
}

原题目：hdoj 1686 Oulipo