[TCO2013]DirectionBoard

#include<stdio.h>
#include<string>
#include<vector>
#include<queue>
#include<string.h>
using namespace std;
const int inf=2147483647;
int h[510],nex[3010],to[3010],cap[3010],cos[3010],M=1,S,T;
void ins(int a,int b,int c,int d){
	M++;
	to[M]=b;
	cap[M]=c;
	cos[M]=d;
	nex[M]=h[a];
	h[a]=M;
}
void add(int a,int b,int c,int d){
	ins(a,b,c,d);
	ins(b,a,0,-d);
}
int dis[510],n,sum,cost;
bool aug[510];
struct pr{
	int x,d;
	pr(int u=0){x=u;d=dis[u];}
}t;
bool operator<(pr a,pr b){return a.d>b.d;}
priority_queue<pr>q;
bool bfs(){
	int x,i;
	memset(dis,63,sizeof(dis));
	dis[T]=0;
	q.push(T);
	while(!q.empty()){
		t=q.top();
		q.pop();
		x=t.x;
		if(dis[x]!=t.d)continue;
		for(i=h[x];i;i=nex[i]){
			if(cap[i^1]&&dis[x]-cos[i]<dis[to[i]]){
				dis[to[i]]=dis[x]-cos[i];
				q.push(to[i]);
			}
		}
	}
	sum+=dis[S];
	for(x=1;x<=n;x++){
		for(i=h[x];i;i=nex[i])cos[i]+=dis[to[i]]-dis[x];
	}
	return dis[S]!=dis[0];
}
int dfs(int x,int f){
	if(f==0)return 0;
	if(x==T){
		cost+=f*sum;
		return f;
	}
	int us=0,i,t;
	aug[x]=1;
	for(i=h[x];i;i=nex[i]){
		if(!cos[i]&&cap[i]&&!aug[to[i]]){
			t=dfs(to[i],min(cap[i],f-us));
			cap[i]-=t;
			cap[i^1]+=t;
			us+=t;
			if(us==f)break;
		}
	}
	if(us==f)aug[x]=0;
	return us;
}
int costflow(){
	do{
		do{
			memset(aug,0,sizeof(aug));
		}while(dfs(S,inf));
	}while(bfs());
	return cost;
}
const int g[4][2]={{0,-1},{0,1},{-1,0},{1,0}};
int type(char c){
	if(c==‘L‘)return 0;
	if(c==‘R‘)return 1;
	if(c==‘U‘)return 2;
	return 3;
}
class DirectionBoard{
	public:
		int getMinimum(vector<string>mp){
			int n,m,i,j,k,x,y,t;
			n=mp.size();
			m=mp[0].length();
			S=n*m*2+1;
			T=S+1;
			::n=T;
			for(i=0;i<n;i++){
				for(j=0;j<m;j++){
					add(S,i*m+j+1,1,0);
					t=type(mp[i][j]);
					for(k=0;k<4;k++){
						x=(i+g[k][0]+n)%n;
						y=(j+g[k][1]+m)%m;
						add(i*m+j+1,x*m+y+1+n*m,1,k!=t);
					}
					add(i*m+j+1+n*m,T,1,0);
				}
			}
			return costflow();
		}
};
/*
int main(){
	vector<string>vt;
	char s[20];
	DirectionBoard cl;
	while(~scanf("%s",s))vt.push_back(s);
	printf("%d",cl.getMinimum(vt));
}
*/