Oulipo

Time Limit: 1000MS

 

Memory Limit: 65536K

Total Submissions: 28155

 

Accepted: 11251

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

KMP模板题，没有比这个更模板的了。。。

唯一要提醒自己的是最后模式串和原串走的时候j是一直往前走的，不回头！怎么就记不住，每次都是搞了两层循环，然后TLE，你这么搞之前搞的那个next数组有什么用，动脑袋想一想啊光速小子。

代码：

#include
#include
#include
#include
#include
using namespace std;

char moshi[10005];
char pipei[1000005];

int result;
int next_moshi[10005];

void get_next()
{
int i,j=-1;
int len=strlen(moshi);
next_moshi[0]=-1;

for(i=0;i<len;)  
{  
    if(j==-1||moshi\[i\]==moshi\[j\])  
    {  
        i++;  
        j++;

        if(moshi\[i\]==moshi\[j\])  
        {  
            next\_moshi\[i\]=next\_moshi\[j\];  
        }  
        else  
        {  
            next\_moshi\[i\]=j;  
        }  
    }  
    else  
    {  
        j=next\_moshi\[j\];  
    }  
}  

}

void get_result()
{
int i=0,j=0;

int len\_pipei=strlen(pipei);  
int len\_moshi=strlen(moshi);

while(j<len\_pipei)  
{  
    if(moshi\[i\]==pipei\[j\])  
    {  
        i++;  
        j++;  
    }  
    else  
    {  
        if(next\_moshi\[i\]==-1)  
        {  
            i=0;  
            j++;  
        }  
        else  
        {  
            i=next\_moshi\[i\];  
        }  
    }  
    if(i>=len\_moshi)  
    {  
        result++;  
        i=next\_moshi\[len\_moshi\];  
    }  
}  

}

int main()
{
int Test;
scanf("%d",&Test);

while(Test--)  
{  
    result=0;

    scanf("%s%s",moshi,pipei);

    get\_next();  
    get\_result();

    cout<<result<<endl;  
}  
return 0;  

}

版权声明：本文为博主原创文章，未经博主允许不得转载。