tjut 3468

来源：互联网发布：psv舰队淘宝编辑：程序博客网时间：2024/06/09 15:09
#include <cstring>  #include <cstdio>  #include <queue>  #include <cstdlib>  #include <cctype>  #define MAXN 105*105*2  #define MAXM 105*105*100  #define inf 0x3f3f3f3f  using namespace std;  struct node  {      int u,v,f;  };  node e[MAXM];  int first[MAXN],next[MAXM];  int gap[MAXN],d[MAXN],curedge[MAXN],pre[MAXN];  int cc, n,m;  inline void add_edge(int u,int v,int f)  {      e[cc].u=u;      e[cc].v=v;      e[cc].f=f;      next[cc]=first[u];      first[u]=cc;      cc++;        e[cc].u=v;      e[cc].v=u;      e[cc].f=0;      next[cc]=first[v];      first[v]=cc;      cc++;    }  int ISAP(int s,int t,int n)  {      int cur_flow,flow_ans=0,u,tmp,neck,i,v;      memset(d,0,sizeof(d));      memset(gap,0,sizeof(gap));      memset(pre,-1,sizeof(pre));      for(i=0;i<=n;i++)          curedge[i]=first[i];      gap[0]=n+1;      u=s;      while(d[s]<=n)      {          if(u==t)          {              cur_flow=inf;              for(i=s;i!=t;i=e[curedge[i]].v)              {                  if(cur_flow>e[curedge[i]].f)                  {                      neck=i;                      cur_flow=e[curedge[i]].f;                  }              }              for(i=s;i!=t;i=e[curedge[i]].v)              {                  tmp=curedge[i];                  e[tmp].f-=cur_flow;                  e[tmp^1].f+=cur_flow;              }              flow_ans+=cur_flow;              u=neck;          }          for(i=curedge[u];i!=-1;i=next[i])          {              v=e[i].v;              if(e[i].f&&d[u]==d[v]+1)                  break;          }          if(i!=-1)          {              curedge[u]=i;              pre[v]=u;              u=v;          }          else          {              if(0==--gap[d[u]])                  break;              curedge[u]=first[u];              for(tmp=n+5,i=first[u];i!=-1;i=next[i])                  if(e[i].f)                      tmp=min(tmp,d[e[i].v]);              d[u]=tmp+1;              ++gap[d[u]];              if(u!=s)                  u=pre[u];          }      }      return flow_ans;  }  char map[105][105];  int rally[105*105];  int gold[105*105];  int pos[105*105];  int dist[55][105*105];  int vis[105][105];  int xx[4]={0,1,0,-1};  int yy[4]={1,0,-1,0};  int trans(char word)  {      if(word>='A'&&word<='Z')          return word-'A';      else          return word-'a'+26;  }  void bfs(int s)  {      queue<int> q;      memset(vis,0,sizeof(vis));      memset(dist[s],inf,sizeof(dist[s]));      int t=pos[s];      vis[t/m][t%m]=1;      q.push(t);      dist[s][t]=0;      while(!q.empty())      {            int u=q.front();          q.pop();          int x=u/m;          int y=u%m;          int i;          for(i=0;i<4;i++)          {              int nx=x+xx[i];              int ny=y+yy[i];              if(nx<0||nx>=n||ny<0||ny>=m)                  continue;              if(vis[nx][ny]||map[nx][ny]=='#')                  continue;              vis[nx][ny]=1;              dist[s][nx*m+ny]=dist[s][x*m+y]+1;              q.push(nx*m+ny);          }      }  }  int main()  {      while(scanf("%d%d",&n,&m)!=EOF)      {          memset(first,-1,sizeof(first));          memset(next,-1,sizeof(next));          cc=0;          memset(pos,0,sizeof(pos));          int i,j;          int cnt1=0;          int cnt2=0;            for(i=0;i<n;i++)          {              scanf("%s",map[i]);              for(j=0;j<m;j++)              {                  if(isalpha(map[i][j]))                  {                      pos[trans(map[i][j])]=i*m+j;                      cnt1++;                  }                  else if(map[i][j]=='*')                  {                      gold[cnt2]=i*m+j;                      cnt2++;                  }              }          }          for(i=0;i<cnt1;i++)              bfs(i);          int flag=1;          for(i=1;i<=cnt1-1;i++)          {              for(j=0;j<cnt2;j++)              {                  if(dist[i][gold[j]]+dist[i-1][gold[j]]==dist[i-1][pos[i]])                  {                      add_edge(i,cnt1+j,1);                  }                  if(dist[i-1][pos[i]]==inf)                  {                      flag=0;                  }              }          }          if(!flag)          {              printf("-1\n");              continue;          }          int s=0,t=cnt1+cnt2;          for(i=1;i<=cnt1-1;i++)              add_edge(s,i,1);          for(i=0;i<cnt2;i++)              add_edge(cnt1+i,t,1);          int res=ISAP(s,t,t);          printf("%d\n",res);        }      return 0;  }
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