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POJ 3461 Oulipo

时间:2016-05-04 22:43:18      阅读:218      评论:0      收藏:0      [点我收藏+]

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E - Oulipo
Time Limit:1000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u

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

 

 
 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 using namespace std;
 6 #define MAXN 20222200
 7 int next[MAXN];
 8 char s[MAXN],p[MAXN];
 9 int read(){
10     register int f=1,x=0;
11     register char ch=getchar();
12     while(ch>9||ch<0){if(ch==-) f=-1;ch=getchar();}
13     while(ch>=0&&ch<=9)x=x*10+ch-0,ch=getchar();
14     return x*f;
15 }
16 void get_next(){
17     int i=0,j=-1;
18     next[0]=-1;
19     int len=strlen(p);
20     while(i<len){
21         if(j==-1||p[i]==p[j]){
22             i++;j++;
23             next[i]=j;
24         }
25         else j=next[j];
26     }    
27 }
28 int kmp(){
29     get_next();
30     int i=0,j=0,ans=0;
31     int len=strlen(s);
32     int   m=strlen(p);
33     while(i<len&&j<m){
34         if(j==-1||s[i]==p[j]){
35             i++;j++;
36         }
37         else j=next[j];
38         if(j==m) ans++,j=next[j];
39     }
40     return ans;
41 }
42 int main()
43 {//kmp求子串出现次数 
44        int n=read();
45        while(n--){
46            scanf("%s%s",p,s);
47            printf("%d\n",kmp());
48        }
49        return 0;
50 }

 

POJ 3461 Oulipo

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原文地址:http://www.cnblogs.com/shenben/p/5459921.html

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