int totalNQueens(int n) {
vector<int> col(n, 0);
vector<int> cross1(n*2-1, 0);
vector<int> cross2(n*2-1, 0);
res = 0;
dfs(0, n, col, cross1, cross2);
return res;
}
bool GameState::isOnBorder(Vector2 point, Direction direction) const
{
Vector2 point2 = point.getNeighbor(direction);
if(!isOnBorder_(point) || !isOnBorder_(point2))
return false;
if(!(direction & 1))
return true;
Vector2 cross1(point.x, point2.y);
Vector2 cross2(point2.x, point.y);
return isOnBorder_(cross1) && isOnBorder_(cross2);
}
