hdu4057Rescue the Rabbit(ac自动机+dp)

链接

当时是因为没有做出来这道题才开了自动机的专题，现在看看还是比较简单的。

因为每个病毒串只算一次，只有10个病毒串，可以状压一下哪些状态是可以达到的，最后取一个最大值。

#include <iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<stdlib.h>
#include<vector>
#include<cmath>
#include<queue>
#include<set>
#include<string>
using namespace std;
#define N 1005
#define LL long long
#define INF 0xfffffff
const double eps = 1e-8;
const double pi = acos(-1.0);
const double inf = ~0u>>2;
const int child_num = 4;
char vir[115];
int v[12];
class AC
{
    private:
    int ch[N][child_num];
    int fail[N];
    int Q[N];
    int val[N];
    int sz;
    int id[128];
    int dp[2][N][1<<10];
    char s[N];
    public:
    void init()
    {
        fail[0] = 0;
        id['A'] = 0,id['G'] = 1,id['T'] = 2,id['C'] = 3;
    }
    void reset()
    {
        memset(ch[0],0,sizeof(ch[0]));
        memset(val,0,sizeof(val));
        sz = 1;
    }
    void insert(char *a,int key)
    {
        int p = 0;
        for(; *a ; a++)
        {
            int d= id[*a];
            if(ch[p][d]==0)
            {
                memset(ch[sz],0,sizeof(ch[sz]));
                s[sz] = *a;
                ch[p][d] = sz++;
            }
            p = ch[p][d];
        }
        val[p] = (1<<key);
    }
    void construct()
    {
        int i,head=0,tail = 0;
        for(i = 0; i  < child_num ;i++)
        {
            if(ch[0][i])
            {
                fail[ch[0][i]] = 0;
                Q[tail++] = ch[0][i];
            }
        }
        while(head!=tail)
        {
            int u = Q[head++];
            val[u]|=val[fail[u]];
            for(i = 0; i < child_num ; i++)
            {
                if(ch[u][i])
                {
                    fail[ch[u][i]] = ch[fail[u]][i];
                    Q[tail++] = ch[u][i];
                }
                else ch[u][i] = ch[fail[u]][i];
            }
        }
    }
    void work(int n,int m)
    {
        int i,j,g;
        memset(dp,0,sizeof(dp));
        dp[0][0][0] = 1;
        for(i = 0 ;i < n ;i++)
        {
            memset(dp[(i+1)%2],0,sizeof(dp[(i+1)%2]));
            for(j = 0 ;j < sz ; j++)
            {
                for(int e = 0 ; e < (1<<m) ; e++)
                {
                    if(!dp[i%2][j][e]) continue;
                    for(g = 0 ; g < child_num ; g++)
                    {
                        int o = val[ch[j][g]];
                        dp[(i+1)%2][ch[j][g]][e|o] = dp[i%2][j][e];
                    }
                }
            }
        }
        int cnt = -INF;
        for(i = 0 ;i < sz ; i++)
        {
            for(j = 0 ;j < (1<<m) ; j++)
            {
                int ans = 0;
                if(!dp[n%2][i][j]) continue;
                for(g = 0 ; g < m ;g++)
                {
                    if(j&(1<<g))
                    ans+=v[g];
                }
                cnt = max(ans,cnt);
            }
        }
        if(cnt<0)
        puts("No Rabbit after 2012!");
        else
        printf("%d
",cnt);
    }
}ac;
int main()
{
    int n,i,m;
    ac.init();
    while(scanf("%d%d",&m,&n)!=EOF)
    {
        ac.reset();
        for(i = 1;i <= m ;i++)
        {
            scanf("%s%d",vir,&v[i-1]);
            ac.insert(vir,i-1);
        }
        ac.construct();
        ac.work(n,m);
    }
    return 0;
}