UVa 10679 - I Love Strings!!

题目：给你一个目标串，和一些模式串，问每个模式串是否在目标串中出现。

分析：字符串，AC自动机。一开始用KMP算法，TLE了才发现会超时，改用AC自动机；

直接利用AC自动机存储，查询即可，然后按顺序输出；

如果模式串中有重复的，直接利用并查集合并即可，只须判断父节点。

说明：╮(╯▽╰)╭计算复杂度时，数据组数被忽略了；注意初始化。

#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>

using namespace std;

char s[100002],t[1002];

#define nodesize 40004        //节点个数
#define dictsize 52           //字符集大小 

typedef struct node1
{
    int    flag;              //值域
    node1* fail;
    node1* next[dictsize];
}tnode;
tnode  dict[nodesize+1];
tnode* Q[nodesize+1];
int    ID[256];
int    visit[1002];
int    father[1002];

class AC_DFA
{
    private:
        int    size;
        tnode* root;
    public:
        AC_DFA() {makeID();init();}
        void makeID() {
            for ( int i = 0 ; i < 26 ; ++ i ) {
                ID['a'+i] = i;
            	ID['A'+i] = i+26;
			}
        }
        void init() {
            memset( dict, 0, sizeof( dict ) );
            root=NULL; size=0; root=newnode();
            for ( int i = 0 ; i < 1001 ; ++ i )
            	father[i] = i;
        }
        tnode* newnode() {
            dict[size].fail = root;
            return &dict[size ++];
        }
        void insert( char* word, int id ) {
            tnode* now = root;
            for ( int i = 0 ; word[i] ; ++ i ) {
                if ( !now->next[ID[word[i]]] )
                    now->next[ID[word[i]]] = newnode();
                now = now->next[ID[word[i]]];
            }
            if ( now->flag ) father[id] = now->flag;
			else now->flag = id;
        }
        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];
                    }
            }
        }
        void query( char* line, int q ) {
            memset( visit, 0, sizeof( visit ) );
            tnode* now = root;
            for ( int i = 0 ; line[i] ; ++ i ) {
        		while ( now && !now->next[ID[line[i]]] ) now = now->fail;
        		now = now?now->next[ID[line[i]]]:root;
                for ( tnode* p = now ; p ; p = p->fail )
                	visit[p->flag] = 1;
            }
            for ( int i = 1 ; i <= q ; ++ i )
            	if ( visit[father[i]] )
					printf("y\n");
				else printf("n\n");
            return;
        }
}dfa;
/* AC_DFA  end */

int main()
{
	int k,q;
	scanf("%d",&k);
	while ( k -- ) {
		dfa.init();

		scanf("%s%d",s,&q);
		for ( int i = 1 ; i <= q ; ++ i ) {
			scanf("%s",t);
			dfa.insert( t, i );
		}
		dfa.setfail();
		dfa.query(s, q);
	}

	return 0;
}

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