hdu4511小明系列故事——女友的考验(ac自动机+最短路）

链接

预处理出来任意两点的距离，然后可以顺着trie树中的节点走，不能走到不合法的地方，另开一维表示走到了哪里，依次来更新。

注意判断一下起点是不是合法。

  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 using namespace std;

 11 #define N 510

 12 #define LL long long

 13 const double eps = 1e-8;

 14 const double pi = acos(-1.0);

 15 const double INF = 1e21;

 16 const int child_num = 51;

 17 double w[55][55];

 18 class AC

 19 {

 20     private:

 21     int ch[N][child_num];

 22     int fail[N];

 23     int val[N];

 24     int id[128];

 25     int Q[N];

 26     double dis[55][N];

 27     int sz;

 28     public:

 29     void init()

 30     {

 31         fail[0] = 0;

 32         for(int i = 0 ; i< child_num ; i++)

 33         id[i] = i;

 34     }

 35     void reset()

 36     {

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

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

 39         sz = 1;

 40     }

 41     void insert(int *a,int k,int key)

 42     {

 43         int i,p=0;

 44         for(i = 1;i <= k; i++)

 45         {

 46             int d = a[i];

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

 48             {

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

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

 51             }

 52             p = ch[p][d];

 53         }

 54         val[p] = key;

 55     }

 56     void construct()

 57     {

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

 59         for(i = 1 ;i < child_num ; i++)

 60         {

 61             if(ch[0][i])

 62             {

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

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

 65             }

 66         }

 67         while(head!=tail)

 68         {

 69             int u = Q[head++];

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

 71             for(i = 1; i < child_num ; i++)

 72             {

 73                 if(ch[u][i])

 74                 {

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

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

 77                 }

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

 79             }

 80         }

 81     }

 82     void work(int n)

 83     {

 84         int i,j,g;

 85         for(i = 1; i <= n ;i++)

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

 87         dis[i][j] = INF;

 88         if(val[1])

 89         {

 90             puts("Can not be reached!");

 91             return ;

 92         }

 93         dis[1][ch[0][1]] = 0;

 94         for(i = 1 ; i <= n ;i++)

 95         {

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

 97             {

 98                 for(g = 1; g <= n ;g++)

 99                 {

100                     int np = ch[j][g];

101                     if(val[np]) continue;

102                     dis[g][np] = min(dis[g][np],dis[i][j]+w[i][g]);

103                 }

104             }

105         }

106         double ans = INF;

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

108         {

109             ans = min(ans,dis[n][i]);

110         }

111         if(fabs(ans-INF)<eps) puts("Can not be reached!");

112         else

113         printf("%.2f\n",ans);

114     }

115 }ac;

116 struct node

117 {

118     double x,y;

119 }pp[55];

120 double cdis(node a,node b)

121 {

122     return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));

123 }

124 int a[10];

125 int main()

126 {

127     int n,m,k,i,j;

128     ac.init();

129     while(scanf("%d%d",&n,&m)&&n&&m)

130     {

131         ac.reset();

132         for(i = 1 ;i <= n; i++)

133         {

134             scanf("%lf%lf",&pp[i].x,&pp[i].y);

135         }

136         for(i = 1; i <= n ;i++)

137             for(j = 1; j <= n ;j++)

138             w[i][j] = cdis(pp[i],pp[j]);

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

140         {

141             scanf("%d",&k);

142             for(j= 1 ;j <= k; j++)

143             scanf("%d",&a[j]);

144             ac.insert(a,k,1);

145         }

146         ac.construct();

147         ac.work(n);

148     }

149     return 0;

150 }

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