HDU 2222 Keywords Search ( AC 自动机 )

来源：互联网发布：淘宝联盟退款编辑：程序博客网时间：2024/05/12 06:51
#include <iostream>#include <cstdio>#include <cstring>using namespace std;#define CHILD_SIZE 26struct TrieNode {    TrieNode* fail_pointer;    TrieNode* childs[CHILD_SIZE];    int occurrences;    TrieNode() {        fail_pointer = NULL;        occurrences = 0;        for ( int i = 0; i < CHILD_SIZE; ++i ) {            childs[i] = NULL;        }    }};TrieNode* root;int head_index = 0;int tail_index = 0;TrieNode* Q[500010];char text[1000010];char keyword[51];void insert_string( char* str ) {    TrieNode* temp = root;    const int str_len = strlen( str );    for ( int i = 0; i < str_len; ++i ) {        const int index = str[i] - 'a';        if ( !temp->childs[index] )            temp->childs[index] = new TrieNode();        temp = temp->childs[index];    }    temp->occurrences++;}void build_ac_automata() {    Q[tail_index++] = root;    while ( tail_index != head_index ) {        TrieNode* parent = Q[head_index++];        for ( int i = 0; i < CHILD_SIZE; ++i ) {            if ( !parent->childs[i] ) continue;            if ( parent == root ) {                parent->childs[i]->fail_pointer = root;            } else {                TrieNode* moving = parent->fail_pointer;                while ( moving ) {                    if ( moving->childs[i] ) {                        parent->childs[i]->fail_pointer = moving->childs[i];                        break;                    }                    moving = moving->fail_pointer;                }                if ( !moving ) {                    parent->childs[i]->fail_pointer = root;                }            }            Q[tail_index++] = parent->childs[i];        }    }}int query_string() {    int res = 0;    TrieNode* node = root;    const int str_len = strlen( text );    for ( int i = 0; i < str_len; ++i ) {        const int index = text[i] - 'a';        while ( node->childs[index] == NULL && node != root ) {            node = node->fail_pointer;        }        node = node->childs[index];        if ( !node ) {            node = root;        }        TrieNode* temp = node;        while ( temp != root && temp->occurrences != -1 ) {            res += temp->occurrences;            temp->occurrences = -1;            temp = temp->fail_pointer;        }    }    return res;}int main() {    int test_num;    int string_num;    scanf( "%d", &test_num );    while ( test_num-- ) {        head_index = 0;        tail_index = 0;        root = new TrieNode();        scanf( "%d", &string_num );        getchar();        for ( int i = 0; i < string_num; ++i ) {            gets( keyword );            insert_string( keyword );        }        build_ac_automata();        scanf( "%s", text );        int res = query_string();        printf( "%d\n", res );    }    return 0;}
0 0