poj 3461 Oulipo

'e'. He was a member of the Oulipo group. A quote from the book:

'T's is not unusual. And they never use spaces.

'A','B', 'C', …, 'Z'} and two finite strings over that alphabet, a wordW and a text T, count the number of occurrences of W inT. All the consecutive characters of W must exactly match consecutive characters ofT. Occurrences may overlap.

• W, a string over {'A','B', 'C', …, 'Z'}, with 1 ≤ |W| ≤ 10,000 (here |W| denotes the length of the stringW).
• T, a string over {'A','B', 'C', …, 'Z'}, with |W| ≤ |T| ≤ 1,000,000.

W in the text T.

3BAPCBAPCAZAAZAZAZAVERDIAVERDXIVYERDIAN

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#include <iostream>#include <cstdio>#include <cmath>#include <cstring>using namespace std;int next[10010],sum=0;void get_next(char *p){    int j,k,plen=strlen(p);    memset(next,0,sizeof(next));    next[0]=-1;    j=0;    k=-1;    while(j<plen)    {        if(k==-1||p[j]==p[k])        {            j++;            k++;            next[j]=k;        }        else            k=next[k];    }}void KMPMatch(char *s,char *p){    int i=0,j=0,slen=strlen(s),plen=strlen(p);    get_next(p);    while(i<slen)    {        if(j==-1||s[i]==p[j])        {            i++;            j++;        }        else        {            j=next[j];        }        if(j==plen)            sum++,j=next[j];    }}int main(){    char S[10010],T[1000100];    int n;    scanf("%d",&n);    while(n-- )    {        scanf("%s%s",S,T);        sum=0;        KMPMatch(T,S);        printf("%d\n",sum);    }    return 0;}