hdu2222:Keywords Search

最新推荐文章于 2025-09-12 18:08:49 发布

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最新推荐文章于 2025-09-12 18:08:49 发布

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文章标签： java

原文链接：http://www.cnblogs.com/fighting-to-the-end/p/5705513.html

本文介绍了一道AC自动机模板题的实现方法，通过详细代码示例展示了如何使用AC自动机进行关键词搜索。该算法适用于批量关键词匹配场景，如搜索引擎中的关键词匹配。

AC自动机模板题。然后queue<int>q放在函数里面就会TLE!!!;

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
#define REP(i,s,t) for(int i=s;i<=t;i++)
#define dwn(i,s,t) for(int i=s;i>=t;i--)
#define clr(x,c) memset(x,c,sizeof(x))
int read(){
    int x=0;char c=getchar();
    while(!isdigit(c)) c=getchar();
    while(isdigit(c)) x=x*10+c-'0',c=getchar();
    return x;
}
const int nmax=1000005;
int ch[nmax][27],fail[nmax],pt=0,F[nmax];
char s[nmax];
void insert(){
    int t=0,len=strlen(s);
    for(int i=0;i<len;i++){
        if(!ch[t][s[i]-'a']) ch[t][s[i]-'a']=++pt;
        t=ch[t][s[i]-'a'];
    }
    F[t]++;
}
queue<int>q;
void getfail(){
    q.push(0);fail[0]=-1;
    while(!q.empty()){
        int x=q.front();q.pop();
        for(int i=0;i<26;i++){
            if(ch[x][i]) q.push(ch[x][i]),fail[ch[x][i]]=x==0?0:ch[fail[x]][i];
            else ch[x][i]=x==0?0:ch[fail[x]][i];
        }
    }
}
void work(){
    scanf("%s",s);
    int len=strlen(s),t=0,ans=0;
    for(int i=0;i<len;i++){
        t=ch[t][s[i]-'a'];
        int temp=t;
        while(temp!=0){
            ans+=F[temp];F[temp]=0;temp=fail[temp];
        }
    }
    printf("%d\n",ans);
}
int main(){
    int t=read();
    while(t--){
        clr(ch,0);clr(F,0);clr(fail,0);pt=0;
        int n=read();
        while(n--) scanf("%s",s),insert();
        getfail();
        /*for(int i=0;i<26;i++) printf("%d ",ch[0][i]);
        for(int i=0;i<=pt;i++) printf("%d ",F[i]);printf("\n");
        for(int i=0;i<=pt;i++) printf("%d ",fail[i]);printf("\n");*/
        work();
    }
    return 0;
}

Keywords Search

Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 131072/131072 K (Java/Others)
Total Submission(s): 51718 Accepted Submission(s): 16656

Problem Description

In the modern time, Search engine came into the life of everybody like Google, Baidu, etc.
Wiskey also wants to bring this feature to his image retrieval system.
Every image have a long description, when users type some keywords to find the image, the system will match the keywords with description of image and show the image which the most keywords be matched.
To simplify the problem, giving you a description of image, and some keywords, you should tell me how many keywords will be match.

Input

First line will contain one integer means how many cases will follow by.
Each case will contain two integers N means the number of keywords and N keywords follow. (N <= 10000)
Each keyword will only contains characters 'a'-'z', and the length will be not longer than 50.
The last line is the description, and the length will be not longer than 1000000.

Output

Print how many keywords are contained in the description.

Sample Input

1 5 she he say shr her yasherhs

Sample Output

Author

Wiskey

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转载于:https://www.cnblogs.com/fighting-to-the-end/p/5705513.html