Poj3461 qulipo (KMP)

Portal  Oulipo

Time limit:1000 ms		Memory limit:65536 K
Total submissions:24124		Accepted:9679

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 o locale 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, o ù s' Abolissait la raison: tout avait l 'air normal mais...

Perec wowould 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 wordWAnd a textT, Count the number of occurrencesWInT. All the consecutive characters of W must exactly match consecutive charactersT. 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 wordW, A string over {'A','B','C',...,'Z'}, With 1 ≤ |W| ≤ 10,000 (here |W| Denotes the length of the stringW).
• One line with the textT, A string over {'A','B','C',...,'Z'}, With |W| ≤|T| ≤ 1,000,000.

Output

For every test case in the input file, the output shoshould contain a single number, on a single line: the number of occurrences of the wordWIn the textT.

Sample Input

3BAPCBAPCAZAAZAZAZAVERDIAVERDXIVYERDIAN

Sample output

130

Source

Bapc 2006 Qualification bare string matching, KMP Algorithm

 1 #include<set> 2 #include<queue> 3 #include<cstdio> 4 #include<cstdlib> 5 #include<cstring> 6 #include<iostream> 7 #include<algorithm> 8 using namespace std; 9 const int N = 1000010;10 #define For(i,n) for(int i=1;i<=n;i++)11 #define Rep(i,l,r) for(int i=l;i<=r;i++)12 char s1[N],s2[N];13 int n,T,m,next[N];14 15 void BuildNext(){16     int pre=0;n=strlen(s1+1),m=strlen(s2+1);17     Rep(i,2,n){18         while(pre&&s1[pre+1]!=s1[i]) pre=next[pre];19         if(s1[pre+1]==s1[i]) pre++;20         next[i]=pre;21     }22 }23 24 void KMP(){25     int is1=0,ans=0;26     For(is2,m){27         while(is1&&s1[is1+1]!=s2[is2]) is1=next[is1];28         if(s1[is1+1]==s2[is2]) is1++;29         if(is1==n){30             ans++;31             is1=next[is1];32         }33     }34     printf("%d\n",ans);35 }36 37 int main(){38     scanf("%d",&T);39     For(i,T){40         scanf("%s%s",s1+1,s2+1);41         BuildNext();42         KMP();43     }44     return 0;45 }

 

Poj3461 qulipo (KMP)