Oulipo (poj 3461&&hdu 1686) KMP

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Oulipo

Time Limit: 1000MS Memory Limit: 65536KTotal Submissions: 24557 Accepted: 9857

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

3BAPCBAPCAZAAZAZAZAVERDIAVERDXIVYERDIAN

Sample Output

130

Source

BAPC 2006 Qualification

得多做几道KMP啊~~

代码：

#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <cmath>#include <string>#include <map>#include <stack>#include <vector>#include <set>#include <queue>#pragma comment (linker,"/STACK:102400000,102400000")#define maxn 1005#define MAXN 2005#define mod 1000000009#define INF 0x3f3f3f3f#define pi acos(-1.0)#define eps 1e-6typedef long long ll;using namespace std;int nextval[11000];char str[1000010],pstr[11000];int T;void get_nextval(){    int plen=strlen(pstr);    int i=0;    nextval[i]=-1;    int j=-1;    while (i<plen)    {        if (j==-1||pstr[i]==pstr[j])        {            i++;            j++;            if (pstr[i]!=pstr[j])                nextval[i]=j;            else                nextval[i]=nextval[j];        }        else            j=nextval[j];    }}int kmp_search(){    int ans=0;    int plen=strlen(pstr);    int slen=strlen(str);    int i=0;    int j=0;    while (i<slen)    {        if (j==-1||pstr[j]==str[i])        {            i++;            j++;        }        else            j=nextval[j];        if (j==plen)        {            ans++;            j=nextval[j];  //hdu2087就这里稍微不同，注意区别        }    }    return ans;}int main(){    scanf("%d",&T);    while (T--)    {        scanf("%s%s",pstr,str);        get_nextval();        printf("%d\n",kmp_search());    }    return 0;}/*3BAPCBAPCAZAAZAZAZAVERDIAVERDXIVYERDIAN*//*3AZAAZAZAZABAPCBAPCVERDIAVERDXIVYERDIAN*/