HDOJ1686 Oulipo KMP

Oulipo

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2620    Accepted Submission(s): 1012

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

 

/* 功能Function Description:     HDOJ-1686
    开发环境Environment:          DEV C++ 4.9.9.1
    技术特点Technique:
    版本Version:
    作者Author:                   可笑痴狂
    日期Date:                      20120814
    备注Notes:
         查找模式字串在主串中出现的次数(可以有部分重叠)-------KMP算法
 */
 
 #include<stdio.h>
 #include<string.h>
 
 char s[1000005],t[10005];
 int next[10005];
 int k;
 
 void get_next(int len)
 {
     int i,j;
     i=0;
     j=-1;
     next[0]=-1;
     while(i<len)
     {
         if(j==-1||t[i]==t[j])
         {
             if(t[++i]==t[++j])
                 next[i]=next[j];
             else
                 next[i]=j;
         }
         else
             j=next[j];
     }
 }
 
 void KMP(int i,int len1,int len2)
 {
     int j=0;
     while(i<len1)
     {
         if(j==-1||s[i]==t[j])   //继续比较后续字符
         {
             ++i;
             ++j;
         }
         else                    //模式串向右移动
             j=next[j];
         if(j==len2)                 //匹配成功
         {
             ++k;
             j=next[j];
         }
     }
 }
 
 int main()
 {
     int len1,len2,n;
     scanf("%d",&n);
     while(n--)
     {

         k=0;
         scanf("%s",t);
         scanf("%s",s);
         len1=strlen(s);
         len2=strlen(t);
         get_next(len2);
         KMP(0,len1,len2);
         printf("%d\n",k);
     }
     return 0;
 }