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| #include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
#define inf 1e9
const int N=3e5+1;
struct edge
{
int from,to,next,cap,flow,cost;
}e[N];
bool vis[N];
int cnt,n,m,sour,sink,head[N],ans,cost,q[N],p[N],d[N],h,t;
const int move[4][2]={-1,0,1,0,0,-1,0,1};
inline void add(int u,int v,int l,int f)
{
e[++cnt]=(edge){u,v,head[u],l,0,f};
head[u]=cnt;
e[++cnt]=(edge){v,u,head[v],0,0,-f};
head[v]=cnt;
}
inline void augment()
{
int detla=inf,c=0;
for(int i=sink;i!=sour;i=e[p[i]].from)
{
detla=min(detla,e[p[i]].cap-e[p[i]].flow);
c+=e[p[i]].cost;
}
for(int i=sink;i!=sour;i=e[p[i]].from)
{
e[p[i]].flow+=detla;
e[((p[i]-1)^1)+1].flow-=detla;
}
ans+=detla;
cost+=detla*c;
}
inline bool find()
{
memset(d,127,sizeof(d));
memset(vis,0,sizeof(vis));
vis[sour]=true;
d[sour]=0;
q[h=t=1]=sour;
while(h<=t)
{
int x=q[h++];
vis[x]=false;
for(int i=head[x];i;i=e[i].next)
{
if(e[i].cap>e[i].flow&&d[x]+e[i].cost<d[e[i].to])
{
if(!vis[e[i].to])
{
vis[e[i].to]=true;
q[++t]=e[i].to;
}
d[e[i].to]=d[x]+e[i].cost;
p[e[i].to]=i;
}
}
}
return d[sink]<inf;
}
inline void sap()
{
while(find())
augment();
}
inline void read(int &x)
{
char ch;
int f=1;
x=0;
do
{
if(ch=='-')
f=-1;
ch=getchar();
}while(!('0'<=ch&&ch<='9'));
do
{
x=(x<<3)+(x<<1)+ch-48;
ch=getchar();
}while('0'<=ch&&ch<='9');
x*=f;
}
inline int get(int x,int y)
{
return (x-1)*m+y;
}
int main()
{
read(n);
read(m);
sour=0;
sink=2*n*m+1;
for(int i=1;i<=n;i++)
{
for(int j=1;j<=m;j++)
{
char c;
cin>>c;
int dir;
add(sour,get(i,j),1,0);
add(get(i,j)+n*m,sink,1,0);
if(c=='U')
dir=0;
else if(c=='D')
dir=1;
else if(c=='L')
dir=2;
else if(c=='R')
dir=3;
for(int k=0;k<4;k++)
{
int x=i+move[k][0],y=j+move[k][1];
if(x==n+1)
x=1;
else if(x==0)
x=n;
if(y==m+1)
y=1;
else if(y==0)
y=m;
if(dir==k)
add(get(i,j),get(x,y)+n*m,1,0);
else
add(get(i,j),get(x,y)+n*m,1,1);
}
}
}
sap();
printf("%d",cost);
return 0;
}
|