1 #include <cstdio> 2 #define INF 2147483647 3 int n,m,N=1,h,t,zl,ans; 4 int a[101][101],fir[10100],d[10100],to[100000],flo[100000],nex[100000],l[10100]; 5 inline void add(int x,int y,int z){    to[++N]=y;flo[N]=z;nex[N]=fir[x];fir[x]=N; 6                                     to[++N]=x;flo[N]=0;nex[N]=fir[y];fir[y]=N;} 7 inline int min(int x,int y){    return(x<y)?x:y;} 8 inline void check(int x,int y,int X,int Y) 9 {10     if(X==0 || Y==0 || X>n || Y>m) return;11     if(a[x][y]!=2 && a[X][Y]!=1)    add((x-1)*m+y,(X-1)*m+Y,1); 12 }13 bool bfs()14 {15     for(int i=1;i<=n*m+1;i++) d[i]=0;16     for(h=1,t=1,l[1]=0,d[0]=1;h<=t;h++)17         for(int i=fir[l[h]];i;i=nex[i])18             if(!d[to[i]] && flo[i])19                 l[++t]=to[i],d[l[t]]=d[l[h]]+1;20     return d[n*m+1];21 }22 int dfs(int now,int flow,int sum)23 {24     if(now==n*m+1)    return flow;25     for(int i=fir[now];i && (sum<flow);i=nex[i])26     if(d[to[i]]==d[now]+1 && flo[i])27         zl=dfs(to[i],min(flow-sum,flo[i]),0),sum+=zl,flo[i]-=zl,flo[i^1]+=zl;28     if(sum==0) d[now]=0;29     return sum;30 }31 int main()32 {33     scanf("%d%d",&n,&m);34     for(int i=1;i<=n;i++)35         for(int j=1;j<=m;j++)36         {37             scanf("%d",&a[i][j]);38             if(a[i][j]==1) add(0,(i-1)*m+j,INF);39             if(a[i][j]==2) add((i-1)*m+j,n*m+1,INF);40         }41     for(int i=1;i<=n;i++)42         for(int j=1;j<=m;j++)43             check(i,j,i-1,j),check(i,j,i+1,j),check(i,j,i,j-1),check(i,j,i,j+1);44     for(ans=0;bfs();ans+=dfs(0,INF,0));45     printf("%d\n",ans);46     return 0;47 }