POJ-3461-Oulipo KMP

Oulipo

Time Limit: 1000MS Memory Limit: 65536KTotal Submissions: 38603 Accepted: 15551

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 wordW and a textT, count the number of occurrences of W inT. All the consecutive characters of W must exactly match consecutive characters ofT. 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 stringW).
• 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 wordW in the textT.

Sample Input

3BAPCBAPCAZAAZAZAZAVERDIAVERDXIVYERDIAN

Sample Output

130

代码：

#include<iostream>#include<cstring>#include<string>#include<cmath>#include<cstdlib>#include<cstdio>using namespace std;int Next[10005];char t[1000005],p[10005];int tlen,plen;void getNext() {    int j,k;    j=0;    k=-1;    Next[0]=-1;    while(j<plen) {        if(k==-1||p[j]==p[k]) {            j++;            k++;            Next[j]=k;        } else {            k=Next[k];        }    }}int KMP_Index() {    int i=0,j=0;    getNext();    while(i<tlen&&j<plen) {        if(j==-1||t[i]==p[j]) {            i++;            j++;        } else {            j=Next[j];        }    }    if(j==plen)        return i-j;    return -1;}int KMP_Count() {    int ans=0;    int i,j=0;    if(tlen==1&&plen==1) {        if(t[0]==p[0])            return 1;        return 0;    }    getNext();    for(i=0; i<tlen; i++) {        while(j>0&&t[i]!=p[j])            j=Next[j];        if(t[i]==p[j])            j++;        if(j==plen) {            ans++;            j=Next[j];        }    }    return ans;}int main() {    int tt;    scanf("%d",&tt);    while(tt--) {        scanf("%s",p);        scanf("%s",t);        tlen=strlen(t);        plen=strlen(p);        //printf("%d\n",KMP_Index());        printf("%d\n",KMP_Count());    }    return 0;}