hdu 2222 - Keywords Search

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题目：给你一些单词构成的词典，统计出现过的单词个数。

分析：字符串，AC自动机。比较裸的AC自动机详细可参照本空间的：AC自动机总结。

说明：注意每个单词只统计一次。

#include <stdio.h>#include <stdlib.h>#include <string.h>/* AC_DFA define */#define nodesize 250010        //节点个数#define dictsize 26            //符集大小 typedef struct node1{    int    flag;            //值域     node1* fail;    node1* next[dictsize];}tnode;tnode  dict[nodesize+1];tnode* Q[nodesize+1];int    ID[256]; class AC_DFA{    private:        int    size;        tnode* root;    public:        AC_DFA() {            makeID();            memset( dict, 0, sizeof( dict ) );            root=NULL; size=0; root=newnode();        }        void makeID() {            for ( int i = 0 ; i < 26 ; ++ i )                ID['a'+i] = i;        }        void init() {            memset( dict, 0, sizeof( dict ) );            root=NULL; size=0; root=newnode();        }        tnode* newnode() {            dict[size].fail = root;            return &dict[size ++];        }        void insert( char* word, int l ) {            tnode* now = root;            for ( int i = 0 ; i < l ; ++ i ) {                if ( !now->next[ID[word[i]]] )                    now->next[ID[word[i]]] = newnode();                now = now->next[ID[word[i]]];            }now->flag ++;        }        void setfail() {            Q[0] = root; root->fail = NULL;            for ( int move = 0,save = 1 ; move < save ; ++ move ) {                tnode* now = Q[move];                for ( int i = 0 ; i < dictsize ; ++ i )                    if ( now->next[i] ) {                        tnode* p = now->fail;                        while ( p && !p->next[i] ) p = p->fail;                        now->next[i]->fail = p?p->next[i]:root;                        Q[save ++] = now->next[i];                    }else now->next[i] = now==root?root:now->fail->next[i];//构建 Trie图             }        }        int query( char* line, int L ) {//统计字串出现个数，可重复及交叉            int sum = 0;            tnode *temp,*now = root;            for ( int i = 0 ; i < L ; ++ i ) {                now = now->next[ID[line[i]]];                temp = now;                while (temp && temp->flag) {                sum += temp->flag;temp->flag = 0;temp = temp->fail;}            }            return sum;         }};/* AC_DFA  end */char Word[51];char Line[1000001];int main(){    int T,N;    while ( ~scanf("%d",&T) )     for ( int t = 1 ; t <= T ; ++ t ) {        AC_DFA ac;        scanf("%d",&N);        for ( int i = 1 ; i <= N ; ++ i ) {            scanf("%s",Word);            ac.insert( Word, strlen( Word ) );        }        ac.setfail();        scanf("%s",Line);        printf("%d\n",ac.query( Line, strlen(Line) ));    }    return 0;}

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