Oulipo(Kmp)

Oulipo

Time Limit : 3000/1000ms (Java/Other)   Memory Limit : 32768/32768K (Java/Other)

Total Submission(s) : 67   Accepted Submission(s) : 44

Problem 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

题解：最基础的KMP，类似于看小说中的査找文字；注意abab abababab,出现的次数是3，而不是2，所以我们只需要在kmp中到p结尾时直接答案加一就好，而不是重新匹配，这样j跳到失配的上一个位置；重新匹配；

代码：

#include<stdio.h>
#include<string.h>
const int MAXN=10010;
char str[MAXN],buf[MAXN*100];
int len1,len2,cnt,p[MAXN];
void getp(){int i=0,j=-1;
p[0]=-1;
while(i<len2){
    if(j==-1||str[j]==str[i]){
        i++,j++;
        p[i]=j;
    }
    else j=p[j];
}
}
void kmp(){
    getp();
    int i=0,j=0;
    while(i<len1){
        if(j==-1||buf[i]==str[j]){
            i++,j++;
            if(j==len2)cnt++;
        }
        else j=p[j];
    }
}
int main(){
    int T;
    scanf("%d",&T);
    while(T--){cnt=0;
        scanf("%s%s",str,buf);
        len1=strlen(buf);
        len2=strlen(str);
        kmp();
        printf("%d
",cnt);
    }
    return 0;
}

#include<iostream>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace  std;
typedef long long LL;
#define mem(x,y) memset(x,y,sizeof(x))
#define SI(x) scanf("%d",&x)
#define PI(x) printf("%d",x)
const int INF=0x3f3f3f3f;
const int MAXN=1000010;
int p[MAXN];

void getp(char* s){
    int len=strlen(s);
    int i=0,j=-1;
    p[0]=-1;
    while(i<len){
        if(j==-1||s[i]==s[j]){
            i++;j++;
            p[i]=j;
        }
        else j=p[j];
    }
}
void kmp(char *s,char* m,int& ans){
    int len=strlen(m);
    getp(s);
    int len2=strlen(s);
    int j=0,i=0;
    while(i<len){
        if(j==-1||s[j]==m[i]){
            i++;j++;
            if(j==len2){
                ans++;
            }
        }
        else j=p[j];
    }
}
int main(){
    char s[MAXN];
    char m[MAXN];
    int T;
    SI(T);
    while(T--){
        scanf("%s%s",s,m);
        int ans=0;
        kmp(s,m,ans);
        printf("%d
",ans);
    }
    return 0;
}