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| const int N = 1510,LG = 21;
int n,m,q,seed;
char s[N][N];
int dx[4] = {-1,+1,+0,+0};
int dy[4] = {+0,+0,-1,+1};
inline int id(int x,int y){
return m*(x-1)+y;
}
struct{
int to,nex;
}edge[N*N*3];
int head[N*N],edge_num,ind[N*N];
inline void add(int x,int y){
edge[++edge_num].to = y;
edge[edge_num].nex = head[x];
head[x] = edge_num;
}
int dfn[N*N],low[N*N],st[N*N],id_scc[N*N],dtop,stop,col_cnt;
inline void tarjan(int now){
dfn[now] = low[now] = ++dtop;
st[++stop] = now;
for(int i=head[now];i;i=edge[i].nex){
int tto = edge[i].to;
if(!dfn[tto]){
tarjan(tto);
low[now] = Min(low[tto],low[now]);
}
else if(!id_scc[tto]) low[now] = Min(low[now],dfn[tto]);
}
if(low[now]==dfn[now]){
++col_cnt;
while(st[stop]^now){
id_scc[st[stop]] = col_cnt;
--stop;
}
id_scc[st[stop]] = col_cnt;
--stop;
}
head[now] = 0;
}
struct node{
int ls,rs;
}tr[N*N*LG];
int rt[N*N],cnt;
inline int merge(int u,int v,int nl,int nr){
if(!u || !v) return u|v;
if(u==v) return u;
int p = ++cnt;
if(nl==nr){
tr[p].ls = tr[u].ls | tr[v].ls;
return p;
}
int mid = (nl+nr) >> 1;
tr[p].ls = merge(tr[u].ls,tr[v].ls,nl,mid);
tr[p].rs = merge(tr[u].rs,tr[v].rs,mid+1,nr);
return p;
}
inline void insert(int &p,int nl,int nr,int x){
if(!p) p = ++cnt;
int mid = (nl+nr) >> 1;
if(nl==nr){
tr[p].ls = 1;
return ;
}
if(x<=mid) insert(tr[p].ls,nl,mid,x);
else insert(tr[p].rs,mid+1,nr,x);
}
inline int query(int p,int nl,int nr,int x){
if(!p) return 0;
int mid = (nl+nr) >> 1;
if(nl==nr) return tr[p].ls;
if(x<=mid) return query(tr[p].ls,nl,mid,x);
else return query(tr[p].rs,mid+1,nr,x);
}
inline void topo(){
queue <int> q;
for(int i=1;i<=col_cnt;++i){
insert(rt[i],1,col_cnt,i);
if(!ind[i]) q.push(i);
}
while(!q.empty()){
int now = q.front();
q.pop();
for(int i=head[now];i;i=edge[i].nex){
int tto = edge[i].to;
rt[tto] = merge(rt[tto],rt[now],1,col_cnt);
--ind[tto];
if(!ind[tto]) q.push(tto);
}
}
}
int main(){
read(n,m,q,seed);
init(seed);
for(int i=1;i<=n;++i){
scanf("%s",s[i]+1);
for(int j=1;j<=m;++j){
for(int t=0;t<4;++t){
if(s[i][j]=='U' && t==0) continue;
if(s[i][j]=='D' && t==1) continue;
if(s[i][j]=='L' && t==2) continue;
if(s[i][j]=='R' && t==3) continue;
int tx = i+dx[t];
int ty = j+dy[t];
if(tx<1 || tx>n || ty<1 || ty>m) continue;
add(id(i,j),id(tx,ty));
}
}
}
for(int i=1;i<=n;++i){
for(int j=1;j<=m;++j){
if(!dfn[id(i,j)]) tarjan(id(i,j));
}
}
edge_num = 0;
for(int i=1;i<=n;++i){
for(int j=1;j<=m;++j){
for(int t=0;t<4;++t){
if(s[i][j]=='U' && t==0) continue;
if(s[i][j]=='D' && t==1) continue;
if(s[i][j]=='L' && t==2) continue;
if(s[i][j]=='R' && t==3) continue;
int tx = i+dx[t];
int ty = j+dy[t];
if(tx<1 || tx>n || ty<1 || ty>m) continue;
if(id_scc[id(i,j)]^id_scc[id(tx,ty)]){
add(id_scc[id(tx,ty)],id_scc[id(i,j)]);
++ind[id_scc[id(i,j)]];
}
}
}
}
topo();
for(int i=1,a,b,x,y;i<=q;++i){
a = get(1,n); b = get(1,m); x = get(1,n); y = get(1,m);
query(rt[id_scc[id(a,b)]],1,col_cnt,id_scc[id(x,y)]) ? putchar('1') : putchar('0');
}
return 0;
}
|
