1066: [SCOI2007]蜥蜴

  1 #include<iostream>
  2 #include<cstdio>
  3 #include<cstring>
  4 #include<algorithm>
  5 #include<queue>
  6 #include<cmath>
  7 using namespace std;
  8 
  9 #define sqr(x) ((x)*(x))
 10 
 11 const int INF=0x7fffffff;
 12 
 13 struct data
 14 {
 15     int to,w,next;
 16 }E[500001];
 17 int node=1,ans;
 18 int head[1000],h[1000],q[1000];
 19 int r,c,d;
 20 int mp[30][30],mark[30][30];
 21 
 22 void insert(int u,int v,int w)
 23 {
 24     E[++node]=(data){v,w,head[u]};
 25     head[u]=node;
 26     E[++node]=(data){u,0,head[v]};
 27     head[v]=node;
 28 }
 29 
 30 bool bfs()
 31 {
 32     int i;
 33     memset(h,-1,sizeof(h));
 34     queue<int> Q;
 35     Q.push(0);
 36     h[0]=0;
 37     while(!Q.empty())
 38     {
 39         int p=Q.front();
 40         Q.pop();
 41         i=head[p];
 42         while(i)
 43         {
 44             if(E[i].w&&h[E[i].to]==-1)
 45             {
 46                 Q.push(E[i].to);
 47                 h[E[i].to]=h[p]+1;
 48             }
 49             i=E[i].next;
 50         }
 51     }
 52     if(h[801]==-1) return 0;
 53     return 1;
 54 }
 55 
 56 int dfs(int x,int f)
 57 {
 58     if(x==801) return f;
 59     int i=head[x];
 60     int w,used=0;
 61     while(i)
 62     {
 63         if(E[i].w&&h[E[i].to]==h[x]+1)
 64         {
 65             w=f-used;
 66             w=dfs(E[i].to,min(w,E[i].w));
 67             E[i].w-=w;
 68             E[i^1].w+=w;
 69             used+=w;
 70             if(used==f) return f;
 71         }
 72         i=E[i].next;
 73     }
 74     if(!used) h[x]=-1;
 75     return used;
 76 }
 77 
 78 void dinic()
 79 {
 80     while(bfs()) ans-=dfs(0,INF);
 81 }
 82 
 83 int main()
 84 {
 85     scanf("%d %d %d",&r,&c,&d);
 86     char ch[30];
 87     for(int i=1;i<=r;i++)
 88     {
 89         scanf("%s",ch+1);
 90         for(int j=1;j<=c;j++)
 91             mp[i][j]=ch[j]-‘0‘;
 92     }
 93     int tot=0;
 94     for(int i=1;i<=r;i++)
 95         for(int j=1;j<=c;j++)
 96             mark[i][j]=++tot;
 97     for(int i=1;i<=r;i++)
 98     {
 99         scanf("%s",ch+1);
100         for(int j=1;j<=c;j++)
101             if(ch[j]==‘L‘)
102             {
103                 ans++;
104                 insert(0,mark[i][j],1);
105             }
106     }
107     for(int i=1;i<=r;i++)
108         for(int j=1;j<=c;j++)
109             if(mp[i][j])
110             {
111                 insert(mark[i][j],mark[i][j]+400,mp[i][j]);
112                 if(i-d<1||i+d>r||j-d<1||j+d>c)
113                     insert(mark[i][j]+400,801,INF);
114             }
115     for(int x1=1;x1<=r;x1++)
116         for(int y1=1;y1<=c;y1++)
117             for(int x2=1;x2<=r;x2++)
118                 for(int y2=1;y2<=c;y2++)
119                     if((x1!=x2||y1!=y2)&&sqr(x1-x2)+sqr(y1-y2)<=sqr(d)&&mp[x1][y1]&&mp[x2][y2])
120                         insert(mark[x1][y1]+400,mark[x2][y2],INF);
121     dinic();
122     printf("%d\n",ans);
123     return 0;
124 }