#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <functional>
#include <complex>
#include <queue>
#include <stack>
#include <cmath>
#include <cassert>
#include <cstring>
using namespace std;
typedef long long LL;
typedef complex<double> CMP;
class MazeMaker { public:
int longestPath(vector <string> maze, int startRow, int startCol, vector <int> moveRow, vector <int> moveCol)
{
const int H = maze.size();
const int W = maze[0].size();
typedef pair<int,int> point;
int cell = 0;
for(int y=0; y<H; ++y)
for(int x=0; x<W; ++x)
if( maze[y][x] == '.' )
++cell;
vector<point> q(1, point(startRow, startCol));
set<point> visited; visited.insert(q[0]);
for(int step=0 ;; ++step)
{
vector<point> q2;
for(int i=0; i<q.size(); ++i)
for(int j=0; j<moveRow.size(); ++j)
{
int yy = q[i].first+moveRow[j];
int xx = q[i].second+moveCol[j];
point pp( yy, xx );
if( visited.count(pp) || yy<0 || H<=yy || xx<0 || W<=xx || maze[yy][xx]!='.' )
continue;
visited.insert(pp);
q2.push_back(pp);
}
q.swap(q2);
if( q.empty() )
return (visited.size()==cell ? step : -1);
}
assert(false);
}
};
// BEGIN CUT HERE
#include <ctime>
double start_time; string timer()
{ ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
{ os << "{ ";
for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
void verify_case(const int& Expected, const int& Received) {
bool ok = (Expected == Received);
if(ok) cerr << "PASSED" << timer() << endl; else { cerr << "FAILED" << timer() << endl;
cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
#define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
#define END verify_case(_, MazeMaker().longestPath(maze, startRow, startCol, moveRow, moveCol));}
int main(){
CASE(0)
string maze_[] = {"...",
"...",
"..."};
vector <string> maze(maze_, maze_+sizeof(maze_)/sizeof(*maze_));
int startRow = 0;
int startCol = 1;
int moveRow_[] = {1,0,-1,0};
vector <int> moveRow(moveRow_, moveRow_+sizeof(moveRow_)/sizeof(*moveRow_));
int moveCol_[] = {0,1,0,-1};
vector <int> moveCol(moveCol_, moveCol_+sizeof(moveCol_)/sizeof(*moveCol_));
int _ = 3;
END
CASE(1)
string maze_[] = {"...",
"...",
"..."};
vector <string> maze(maze_, maze_+sizeof(maze_)/sizeof(*maze_));
int startRow = 0;
int startCol = 1;
int moveRow_[] = {1, 0, -1, 0, 1, 1, -1, -1};
vector <int> moveRow(moveRow_, moveRow_+sizeof(moveRow_)/sizeof(*moveRow_));
int moveCol_[] = {0, 1, 0, -1, 1, -1, 1, -1};
vector <int> moveCol(moveCol_, moveCol_+sizeof(moveCol_)/sizeof(*moveCol_));
int _ = 2;
END
CASE(2)
string maze_[] = {"X.X",
"...",
"XXX",
"X.X"};
vector <string> maze(maze_, maze_+sizeof(maze_)/sizeof(*maze_));
int startRow = 0;
int startCol = 1;
int moveRow_[] = {1, 0, -1, 0};
vector <int> moveRow(moveRow_, moveRow_+sizeof(moveRow_)/sizeof(*moveRow_));
int moveCol_[] = {0, 1, 0, -1};
vector <int> moveCol(moveCol_, moveCol_+sizeof(moveCol_)/sizeof(*moveCol_));
int _ = -1;
END
CASE(3)
string maze_[] = {".......",
"X.X.X..",
"XXX...X",
"....X..",
"X....X.",
"......."};
vector <string> maze(maze_, maze_+sizeof(maze_)/sizeof(*maze_));
int startRow = 5;
int startCol = 0;
int moveRow_[] = {1, 0, -1, 0,-2, 1};
vector <int> moveRow(moveRow_, moveRow_+sizeof(moveRow_)/sizeof(*moveRow_));
int moveCol_[] = {0, -1, 0, 1, 3, 0};
vector <int> moveCol(moveCol_, moveCol_+sizeof(moveCol_)/sizeof(*moveCol_));
int _ = 7;
END
CASE(4)
string maze_[] = {"......."};
vector <string> maze(maze_, maze_+sizeof(maze_)/sizeof(*maze_));
int startRow = 0;
int startCol = 0;
int moveRow_[] = {1, 0, 1, 0, 1, 0};
vector <int> moveRow(moveRow_, moveRow_+sizeof(moveRow_)/sizeof(*moveRow_));
int moveCol_[] = {0, 1, 0, 1, 0, 1};
vector <int> moveCol(moveCol_, moveCol_+sizeof(moveCol_)/sizeof(*moveCol_));
int _ = 6;
END
CASE(5)
string maze_[] = {"..X.X.X.X.X.X."};
vector <string> maze(maze_, maze_+sizeof(maze_)/sizeof(*maze_));
int startRow = 0;
int startCol = 0;
int moveRow_[] = {2,0,-2,0};
vector <int> moveRow(moveRow_, moveRow_+sizeof(moveRow_)/sizeof(*moveRow_));
int moveCol_[] = {0,2,0,-2};
vector <int> moveCol(moveCol_, moveCol_+sizeof(moveCol_)/sizeof(*moveCol_));
int _ = -1;
END
CASE(6)
string maze_[] = {".X","X."};
vector <string> maze(maze_, maze_+sizeof(maze_)/sizeof(*maze_));
int startRow = 0;
int startCol = 0;
int moveRow_[] = {1};
vector <int> moveRow(moveRow_, moveRow_+sizeof(moveRow_)/sizeof(*moveRow_));
int moveCol_[] = {1};
vector <int> moveCol(moveCol_, moveCol_+sizeof(moveCol_)/sizeof(*moveCol_));
int _ = 1;
END
CASE(7)
string maze_[] = {".X","X."};
vector <string> maze(maze_, maze_+sizeof(maze_)/sizeof(*maze_));
int startRow = 0;
int startCol = 0;
int moveRow_[] = {1};
vector <int> moveRow(moveRow_, moveRow_+sizeof(moveRow_)/sizeof(*moveRow_));
int moveCol_[] = {0};
vector <int> moveCol(moveCol_, moveCol_+sizeof(moveCol_)/sizeof(*moveCol_));
int _ = -1;
END
}
// END CUT HERE