HDU 2825 Wireless Password(AC自动机+DP)

题目链接

做题，

  1 #include <cstdio>

  2 #include <string>

  3 #include <cstring>

  4 using namespace std;

  5 #define MOD 20090717

  6 int trie[351][26];

  7 int o[351];

  8 int fail[351];

  9 int que[351];

 10 int dp[2][351][1024];

 11 int flag[1024];

 12 int t;

 13 void CL()

 14 {

 15     memset(trie,-1,sizeof(trie));

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

 17     memset(o,0,sizeof(o));

 18     t = 1;

 19 }

 20 void insert(char *s,int num)

 21 {

 22     int root,i,len;

 23     len = strlen(s);

 24     root = 0;

 25     for(i = 0;i < len;i ++)

 26     {

 27         if(trie[root][s[i]-'a'] == -1)

 28         trie[root][s[i]-'a'] = t ++;

 29         root = trie[root][s[i]-'a'];

 30     }

 31     o[root] |= 1<<num;

 32 }

 33 void build_ac()

 34 {

 35     int head,tail,front,i;

 36     head = tail = 0;

 37     for(i = 0;i < 26;i ++)

 38     {

 39         if(trie[0][i] != -1)

 40         {

 41             fail[trie[0][i]] = 0;

 42             que[tail++] = trie[0][i];

 43         }

 44         else

 45         {

 46             trie[0][i] = 0;

 47         }

 48     }

 49     while(head != tail)

 50     {

 51         front = que[head++];

 52         o[front] |= o[fail[front]];

 53         for(i = 0;i < 26;i ++)

 54         {

 55             if(trie[front][i] != -1)

 56             {

 57                 que[tail++] = trie[front][i];

 58                 fail[trie[front][i]] = trie[fail[front]][i];

 59             }

 60             else

 61             {

 62                 trie[front][i] = trie[fail[front]][i];

 63             }

 64         }

 65     }

 66 }

 67 int main()

 68 {

 69     int n,m,r,k,i,j,u,x,y;

 70     char str[101];

 71     for(i = 0;i < 1024;i ++)

 72     {

 73         for(j = 0;j < 10;j ++)

 74         {

 75             if(i&(1<<j)) flag[i] ++;

 76         }

 77     }

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

 79     {

 80         if(n == 0&&m == 0&&r == 0) break;

 81         CL();

 82         for(i = 0;i < m;i ++)

 83         {

 84             scanf("%s",str);

 85             insert(str,i);

 86         }

 87         build_ac();

 88         dp[0][0][0] = 1;

 89         x = 0;y = 1;

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

 91         {

 92             memset(dp[y],0,sizeof(dp[y]));

 93             for(j = 0;j < t;j ++)

 94             {

 95                 for(k = 0;k < (1<<m);k ++)

 96                 {

 97                     if(dp[x][j][k] == 0) continue;

 98                     for(u = 0;u < 26;u ++)

 99                     {

100                         int temp =  trie[j][u];

101                         dp[y][temp][k|o[temp]] += dp[x][j][k];

102                         if(dp[y][temp][k|o[temp]] >= MOD)

103                         dp[y][temp][k|o[temp]] -= MOD;

104                     }

105                 }

106             }

107             swap(x,y);

108         }

109         int ans = 0;

110         for(i = 0;i < t;i ++)

111         {

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

113             {

114                 if(flag[j] >= r)

115                 ans = (ans + dp[x][i][j])%MOD;

116             }

117         }

118         printf("%d\n",ans);

119     }

120     return 0;

121 }

 

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