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Re:AC自动机跑了2000+ms,估计比朴素都慢了悲剧……

Posted by hnust_xiaochaoqun at 2017-09-12 15:18:24 on Problem 1204
In Reply To:AC自动机跑了2000+ms,估计比朴素都慢了悲剧…… Posted by:xuhaoran510 at 2011-03-05 16:27:27
500多ms。。也是ac自动机。

/**
题目:hdu3065 病毒侵袭持续中
链接:http://acm.hdu.edu.cn/showproblem.php?pid=3065
题意:给定一个L C(C <= 1000, L <= 1000)的字母矩阵,
再给定W(W <= 1000)个字符串,保证这些字符串都会在字母矩阵中出现(8种方向),
求它们的出现位置和方向。

思路:


AC自动机好文章:http://www.cppblog.com/menjitianya/archive/2014/07/10/207604.html
*/


//#include<bits/stdc++.h>
#include<cstring>
#include<cstdio>
#include<iostream>
#include<algorithm>
#include<queue>
using namespace std;
#define P pair<int,int>
#define ms(x,y) memset(x,y,sizeof x)
#define LL long long
const int maxn = 1005;
const int mod = 1e9+7;
const int maxnode = maxn*maxn;
const int sigma_size = 26;
struct node
{
    int x, y, dir;
}ans[maxn];
int dir[8][2] = {{-1,0},{-1,1},{0,1},{1,1},{1,0},{1,-1},{0,-1},{-1,-1}};
char s[maxn][maxn];
int sn, sm;
struct AhoCorasickAutomata
{
    int ch[maxnode][sigma_size];
    int val[maxnode];
    int sz;
    int f[maxnode];
    int last[maxnode];
    void clear(){sz = 1; memset(ch[0],0,sizeof ch[0]); }
    int idx(char c){return c-'A'; }

    void insert(char *s,int x)
    {
        int u = 0, n = strlen(s);
        for(int i = 0; i < n; i++){
            int c = idx(s[i]);
            if(!ch[u][c]){
                memset(ch[sz], 0, sizeof ch[sz]);
                val[sz] = 0;
                ch[u][c] = sz++;
            }
            u = ch[u][c];
        }
        val[u] = x;
    }

    void find(int x,int y,int f){
        int j = 0;
        while(x>=0&&x<sn&&y>=0&&y<sm){
            int c = idx(s[x][y]);
            j = ch[j][c];
            if(val[j]) print(j,x,y,f);
            else if(last[j]) print(last[j],x,y,f);
            x = x+dir[f][0];
            y = y+dir[f][1];
        }
    }

    void print(int j,int x,int y,int dir)
    {
        if(j){
            //cnt[val[j]]++;
            ans[val[j]].x = x, ans[val[j]].y = y;
            ans[val[j]].dir = dir;
            print(last[j],x,y,dir);
        }
    }

    void getFail(){
        queue<int> q;
        f[0] = 0;
        for(int c = 0; c < sigma_size; c++){
            int u = ch[0][c];
            if(u){f[u] = 0; q.push(u); last[u] = 0;}
        }

        while(!q.empty()){
            int r = q.front(); q.pop();
            for(int c = 0; c < sigma_size; c++){
                int u = ch[r][c];
                if(!u){
                    ch[r][c] = ch[f[r]][c]; continue;
                }//if(!u) continue;
                q.push(u);
                int v = f[r];
                while(v&&!ch[v][c]) v = f[v];
                f[u] = ch[v][c];
                last[u] = val[f[u]] ? f[u] : last[f[u]];
            }
        }
    }

} ac ;
char t[maxn];
int main()
{
    int w;
    while(scanf("%d%d%d",&sn,&sm,&w)!=EOF)
    {
        for(int i = 0; i < sn; i++) scanf("%s",s[i]);
        ac.clear();
        for(int i = 1; i <= w; i++){
            scanf("%s",t);
            reverse(t,t+strlen(t));///逆向插入,这样当查询的时候,当前的x,y就是起点。而不用回溯获取找起点。
            ///同理,方向的最终结果也要反向再输出。
            ac.insert(t,i);
        }
        ac.getFail();
        for(int i = 0; i < sm; i++){
            ac.find(0,i,4);///向下
            ac.find(sn-1,i,0);///向上
            ac.find(0,i,5);///向左下
            ac.find(0,i,3);///向右下
            ac.find(sn-1,i,1);///向右上
            ac.find(sn-1,i,7);///向左上
        }
        for(int i = 0; i < sn; i++){
            ac.find(i,0,2);///向右
            ac.find(i,sm-1,6);///向左
            ac.find(i,0,3);///右下
            ac.find(i,0,1);///右上
            ac.find(i,sm-1,5);///左下
            ac.find(i,sm-1,7);///左上
        }
        for(int i = 1; i <= w; i++){
            printf("%d %d %c\n",ans[i].x,ans[i].y,(ans[i].dir+4)%8+'A');
        }
    }
    return 0;
}

/*
QWSPILAATIRAGRAMYKEI
AGTRCLQAXLPOIJLFVBUQ
TQTKAZXVMRWALEMAPKCW
LIEACNKAZXKPOTPIZCEO
FGKLSTCBTROPICALBLBC
JEWHJEEWSMLPOEKORORA
LUPQWRNJOAAGJKMUSJAE
KRQEIOLOAOQPRTVILCBZ
QOPUCAJSPPOUTMTSLPSF
LPOUYTRFGMMLKIUISXSW
WAHCPOIYTGAKLMNAHBVA
EIAKHPLBGSMCLOGNGJML
LDTIKENVCSWQAZUAOEAL
HOPLPGEJKMNUTIIORMNC
LOIUFTGSQACAXMOPBEIO
QOASDHOPEPNBUYUYOBXB
IONIAELOJHSWASMOUTRK
HPOIYTJPLNAQWDRIBITG
LPOINUYMRTEMPTMLMNBO
PAFCOPLHAVAIANALBPFS
MARGARITA
ALEMA
BARBECUE
TROPICAL
SUPREMA
LOUISIANA
CHEESEHAM
EUROPA
HAVAIANA
CAMPONESA
*/
















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