hdu4057Rescue the Rabbit(ac自动机+dp)

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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。

  1 #include <iostream>

  2 #include<cstdio>

  3 #include<cstring>

  4 #include<algorithm>

  5 #include<stdlib.h>

  6 #include<vector>

  7 #include<cmath>

  8 #include<queue>

  9 #include<set>

 10 #include<string>

 11 using namespace std;

 12 #define N 1005

 13 #define LL long long

 14 #define INF 0xfffffff

 15 const double eps = 1e-8;

 16 const double pi = acos(-1.0);

 17 const double inf = ~0u>>2;

 18 const int child_num = 4;

 19 char vir[115];

 20 int v[12];

 21 class AC

 22 {

 23     private:

 24     int ch[N][child_num];

 25     int fail[N];

 26     int Q[N];

 27     int val[N];

 28     int sz;

 29     int id[128];

 30     int dp[2][N][1<<10];

 31     char s[N];

 32     public:

 33     void init()

 34     {

 35         fail[0] = 0;

 36         id['A'] = 0,id['G'] = 1,id['T'] = 2,id['C'] = 3;

 37     }

 38     void reset()

 39     {

 40         memset(ch[0],0,sizeof(ch[0]));

 41         memset(val,0,sizeof(val));

 42         sz = 1;

 43     }

 44     void insert(char *a,int key)

 45     {

 46         int p = 0;

 47         for(; *a ; a++)

 48         {

 49             int d= id[*a];

 50             if(ch[p][d]==0)

 51             {

 52                 memset(ch[sz],0,sizeof(ch[sz]));

 53                 s[sz] = *a;

 54                 ch[p][d] = sz++;

 55             }

 56             p = ch[p][d];

 57         }

 58         val[p] = (1<<key);

 59     }

 60     void construct()

 61     {

 62         int i,head=0,tail = 0;

 63         for(i = 0; i  < child_num ;i++)

 64         {

 65             if(ch[0][i])

 66             {

 67                 fail[ch[0][i]] = 0;

 68                 Q[tail++] = ch[0][i];

 69             }

 70         }

 71         while(head!=tail)

 72         {

 73             int u = Q[head++];

 74             val[u]|=val[fail[u]];

 75             for(i = 0; i < child_num ; i++)

 76             {

 77                 if(ch[u][i])

 78                 {

 79                     fail[ch[u][i]] = ch[fail[u]][i];

 80                     Q[tail++] = ch[u][i];

 81                 }

 82                 else ch[u][i] = ch[fail[u]][i];

 83             }

 84         }

 85     }

 86     void work(int n,int m)

 87     {

 88         int i,j,g;

 89         memset(dp,0,sizeof(dp));

 90         dp[0][0][0] = 1;

 91         for(i = 0 ;i < n ;i++)

 92         {

 93             memset(dp[(i+1)%2],0,sizeof(dp[(i+1)%2]));

 94             for(j = 0 ;j < sz ; j++)

 95             {

 96                 for(int e = 0 ; e < (1<<m) ; e++)

 97                 {

 98                     if(!dp[i%2][j][e]) continue;

 99                     for(g = 0 ; g < child_num ; g++)

100                     {

101                         int o = val[ch[j][g]];

102                         dp[(i+1)%2][ch[j][g]][e|o] = dp[i%2][j][e];

103                     }

104                 }

105             }

106         }

107         int cnt = -INF;

108         for(i = 0 ;i < sz ; i++)

109         {

110             for(j = 0 ;j < (1<<m) ; j++)

111             {

112                 int ans = 0;

113                 if(!dp[n%2][i][j]) continue;

114                 for(g = 0 ; g < m ;g++)

115                 {

116                     if(j&(1<<g))

117                     ans+=v[g];

118                 }

119                 cnt = max(ans,cnt);

120             }

121         }

122         if(cnt<0)

123         puts("No Rabbit after 2012!");

124         else

125         printf("%d\n",cnt);

126     }

127 }ac;

128 int main()

129 {

130     int n,i,m;

131     ac.init();

132     while(scanf("%d%d",&m,&n)!=EOF)

133     {

134         ac.reset();

135         for(i = 1;i <= m ;i++)

136         {

137             scanf("%s%d",vir,&v[i-1]);

138             ac.insert(vir,i-1);

139         }

140         ac.construct();

141         ac.work(n,m);

142     }

143     return 0;

144 }

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