POJ3461 Oulipo(字符串匹配KMP)

题目：

Language:Default Oulipo Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 40409   Accepted: 16253 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 Source BAPC 2006 Qualification

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思路：

KMP模板题，求的是子串在原串中出现的次数

代码：

#include
#include
#include
#include
#include
#include
#include
#include
#include
#define mem(a,b) memset(a,b,sizeof(a))
#define inf 0x3f3f3f3f
#define mod 10000007
#define debug() puts("what the fuck!!!")
#define N 1000010
#define ll longlong
using namespace std;
char s1[N],s2[N];
int next[N];
int len1,len2,n,m;
void get_next()
{
    int j=0,k=-1;
    next[0]=-1;
    while(j0&&s2[i]!=s1[j])
            j=next[j];
        if(s1[j]==s2[i])
            j++;
        if(j==len1)
        {
            ans++;
            j=next[j];
        }
    }
    return ans;
}
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%s%s",s1,s2);
        len1=strlen(s1);
        len2=strlen(s2);
        printf("%d\n",KMP_count());
    }
    return 0;
}

2018年03月17日09:21:00更新

换一种写法

#include 
#include 
#include 
#include 
#include 
#include