#include using namespace std; typedef signed long long ll; #undef _P #define _P(...) (void)printf(__VA_ARGS__) #define FOR(x,to) for(x=0;x<(to);x++) #define FORR(x,arr) for(auto& x:arr) #define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++) #define ALL(a) (a.begin()),(a.end()) #define ZERO(a) memset(a,0,sizeof(a)) #define MINUS(a) memset(a,0xff,sizeof(a)) //------------------------------------------------------- int H,W; string S[3030]; int D[3030][3030]; void solve() { int i,j,k,l,r,x,y; string s; cin>>H>>W; FOR(y,H) cin>>S[y+1], S[y+1]='.'+S[y+1]+'.'; FOR(x,W+2) S[0]+='.', S[H+1]+='.'; H+=2; W+=2; FOR(y,H) FOR(x,W) D[y][x]=3030; queue Q; FOR(y,H) FOR(x,W) { if(S[y][x]=='.') D[y][x]=0, Q.push(y*10000+x); } int ma=0; while(Q.size()) { k=Q.front(); Q.pop(); int cy=k/10000,cx=k%10000; FOR(i,4) { int dd[4]={0,1,0,-1}; int ty=cy+dd[i]; int tx=cx+dd[i^1]; if(tx<0 || tx>=W || ty<0||ty>=H || D[ty][tx]<=D[cy][cx]+1) continue; ma=D[ty][tx]=D[cy][cx]+1; Q.push(ty*10000+tx); } } cout<