public bool Equals(Piece other)
{
if (ReferenceEquals(null, other)) {
return false;
}
if (ReferenceEquals(this, other)) {
return true;
}
return other.X == X && other.Y == Y;
}
private static void Advance(
Piece[,] map, HashSet<Piece> friends, HashSet<Piece> enemies, char type,
int dx, int w, int h)
{
foreach (var piece in friends) {
if (map[piece.X + dx, piece.Y] != null
&& map[piece.X + dx, piece.Y].Type != type) {
enemies.Remove(map[piece.X + dx, piece.Y]);
map[piece.X, piece.Y] = null;
piece.X += dx;
map[piece.X, piece.Y] = piece;
return;
}
}
foreach (var piece in friends) {
if (map[piece.X + dx, piece.Y] == null &&
map[piece.X + dx * 2, piece.Y] == null &&
map[piece.X + dx * 3, piece.Y] != null
&& map[piece.X + dx * 3, piece.Y].Type != type) {
map[piece.X, piece.Y] = null;
piece.X += dx;
map[piece.X, piece.Y] = piece;
return;
}
}
foreach (var piece in friends) {
if (map[piece.X + dx, piece.Y] == null
&&
(map[piece.X + dx * 2, piece.Y] == null
|| map[piece.X + dx * 2, piece.Y].Type == type)) {
map[piece.X, piece.Y] = null;
piece.X += dx;
map[piece.X, piece.Y] = piece;
return;
}
}
foreach (var piece in friends) {
map[piece.X, piece.Y] = null;
piece.X += dx;
map[piece.X, piece.Y] = piece;
return;
}
foreach (var piece in friends) {
map[piece.X, piece.Y] = null;
piece.X += dx;
map[piece.X, piece.Y] = piece;
return;
}
}
private void Solve(TextReader input)
{
var hw = input.ReadLine().Split(' ').Select(int.Parse).ToList();
var h = hw[0];
var w = hw[1];
var map = new Piece[w + margin * 2,h + margin * 2];
var piecesMaru = new HashSet<Piece>();
var piecesBatu = new HashSet<Piece>();
for (int y = margin; y < h + margin; y++) {
var line = input.ReadLine();
for (int x = margin; x < w + margin; x++) {
var piece = new Piece { X = x, Y = y, Type = line[x - margin] };
if (piece.Type == 'o') {
piecesMaru.Add(piece);
map[x, y] = piece;
} else if (piece.Type == 'x') {
piecesBatu.Add(piece);
map[x, y] = piece;
}
}
}
while (piecesMaru.Count != 0 && piecesBatu.Count != 0) {
Advance(map, piecesMaru, piecesBatu, 'o', 1, w, h);
Advance(map, piecesBatu, piecesMaru, 'x', -1, w, h);
}
Console.WriteLine(piecesMaru.Count != 0 ? 'o' : 'x');
}
