private static void Fall(DijkstraHelper <int> dijkstra, int x, int y, int dist, int fallDist, int dx1, int dx2)
{
while (y + 1 < ysize && map[y + 1, x] == '.')
{
y++;
fallDist++;
}
if (fallDist <= maxFall)
{
if (fallDist > 1)
{
dx1 = dx2 = x;
}
dijkstra.Add(Encode(x, y, dx1, dx2), dist);
}
}
private static void Solve(TextReader sr, TextWriter sw)
{
string[] strings = sr.ReadLine().Split(' ');
ysize = int.Parse(strings[0]);
xsize = int.Parse(strings[1]);
maxFall = int.Parse(strings[2]);
map = new char[ysize, xsize];
for (int i = 0; i < ysize; i++)
{
string line = sr.ReadLine();
for (int j = 0; j < xsize; j++)
{
map[i, j] = line[j];
}
}
var dijkstra = new DijkstraHelper <int>(xsize * ysize * 120);
dijkstra.Add(Encode(0, 0, 0, 0), 0);
int ans = -1;
while (true)
{
int node = dijkstra.GetNext();
if (node < 0)
{
break;
}
int x, y, dx1, dx2;
Decode(node, out x, out y, out dx1, out dx2);
int curDist = dijkstra.GetDistance(node);
// Console.WriteLine("At " + x + "," + y + " [" + dx1 + "," + dx2 + "] after " + curDist + " digs.");
if (y == ysize - 1)
{
ans = curDist;
break;
}
// Find move interval
int left = x, right = x;
while (left - 1 >= 0 && map[y + 1, left - 1] == '#' && (map[y, left - 1] == '.' || (left - 1 >= dx1 && left - 1 <= dx2)))
{
left--;
}
while (right + 1 < xsize && map[y + 1, right + 1] == '#' && (map[y, right + 1] == '.' || (right + 1 >= dx1 && right + 1 <= dx2)))
{
right++;
}
if (left - 1 >= 0 && (map[y, left - 1] == '.' || (left - 1 >= dx1 && left - 1 <= dx2)) && map[y + 1, left - 1] == '.')
{
Fall(dijkstra, left - 1, y, curDist, 0, left - 1, left - 1);
}
if (right + 1 < xsize && (map[y, right + 1] == '.' || (right + 1 >= dx1 && right + 1 <= dx2)) && map[y + 1, right + 1] == '.')
{
Fall(dijkstra, right + 1, y, curDist, 0, right + 1, right + 1);
}
for (int nx = left; nx <= right; nx++)
{
// Dig the interval [nx,tx] and fall down into tx
for (int tx = nx; tx < right; tx++)
{
Fall(dijkstra, tx, y + 1, curDist + (tx - nx + 1), 1, nx, tx);
}
// Dig the interval [tx,nx] and fall down into tx
for (int tx = left + 1; tx <= nx; tx++)
{
Fall(dijkstra, tx, y + 1, curDist + (nx - tx + 1), 1, tx, nx);
}
}
}
if (ans < 0)
{
sw.WriteLine("No");
}
else
{
sw.WriteLine("Yes " + ans);
}
}
