HDU 3695 Computer Virus on Planet Pandora AC自动机

来源：互联网发布：linux创建多层目录编辑：程序博客网时间：2024/06/01 18:55

题目连接:http://blog.csdn.net/SolarDomo/article/category/6354437

题意:问模式串在主串和主串的逆串中出现多少个
建自动机之后，把正串和反串都跑一边自动机，遍历到的VALUE值的清空

代码：

#include <bits/stdc++.h>#define sf scanf#define pf printfusing namespace std;const int maxn = 250000 + 5,sigma_size = 26;int ch[maxn][sigma_size],value[maxn],tot,fail[maxn];void Init_Trie(){    memset(ch[0],0,sizeof ch[0]);    value[0] = 0;tot = 1;}void Insert(char *s,int v){    int cur = 0,idx;    while(*s){        idx = *s - 'A';        if(!ch[cur][idx]){            memset(ch[tot],0,sizeof ch[tot]);            value[tot] = 0;            ch[cur][idx] = tot++;        }cur = ch[cur][idx];        s++;    }    value[cur]++;}void GetFail(){    queue<int> Q;    Q.push(0);fail[0] = -1;    while(!Q.empty()){        int cur = Q.front();Q.pop();        for(int i = 0;i <sigma_size;++i){            if(ch[cur][i]){                int f = fail[cur];                while(f != -1 && ch[f][i] == 0) f = fail[f];                fail[ch[cur][i]] = (f == - 1) ? 0 : ch[f][i];                Q.push(ch[cur][i]);            }            else{                ch[cur][i] = (cur == 0) ? 0 : ch[fail[cur]][i];            }        }    }}int Search(char *s){    int cur = 0,ret = 0;    while(*s){        int idx = *s - 'A';        cur = ch[cur][idx];        if(value[cur]){            int tmp = cur;            while(tmp){                ret += value[tmp];value[tmp] = 0;                tmp = fail[tmp];            }        }        s++;    }    return ret;}const int maxc = 5100000 + 5;char str[maxc],tmpc;int main(){    int T;sf("%d",&T);    while(T--){        Init_Trie();        int n;sf("%d",&n);        while(n--){            sf("%s",str);            Insert(str,1);        }tmpc = getchar();        int len = 0;        while(tmpc = getchar()){            if(tmpc == '\n') break;            else if(tmpc == '['){                int cnt;sf("%d",&cnt);tmpc = getchar();                while(cnt--){                    str[len++] = tmpc;                }                getchar();            }            else{                str[len++] = tmpc;            }        }str[len] = '\0';        GetFail();        int ret = Search(str);        strrev(str);ret += Search(str);        pf("%d\n",ret);    }}

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