public int TrapRainWater(int[][] heightMap)
{
int rows = heightMap.Length;
int cols = heightMap[0].Length;
if (cols < 3 || rows < 3)
{
return(0);
}
bool[,] visited = new bool[rows, cols];
DuplicatedSortedTree <int[]> heap = new DuplicatedSortedTree <int[]>(new RainComparer(), new RainComparer());
for (int i = 0; i < rows; i++)
{
heap.Add(new int[] { i, 0, heightMap[i][0] });
heap.Add(new int[] { i, cols - 1, heightMap[i][cols - 1] });
visited[i, 0] = true;
visited[i, cols - 1] = true;
}
for (int i = 1; i < cols - 1; i++)
{
heap.Add(new int[] { 0, i, heightMap[0][i] });
heap.Add(new int[] { rows - 1, i, heightMap[rows - 1][i] });
visited[0, i] = true;
visited[rows - 1, i] = true;
}
int ans = 0;
int[] d = new int[] { -1, 0, 1, 0, -1 };
while (heap.Count > 0)
{
var temp = heap.Min;
heap.Remove(temp);
for (int i = 0; i < 4; i++)
{
int r = temp[0] + d[i];
int c = temp[1] + d[i + 1];
if (r >= 0 && r < rows && c >= 0 && c < cols && !visited[r, c])
{
if (heightMap[r][c] < temp[2])
{
ans += temp[2] - heightMap[r][c];
}
visited[r, c] = true;
heap.Add(new int[] { r, c, Math.Max(temp[2], heightMap[r][c]) });
}
}
}
return(ans);
}
public IList <IList <int> > GetSkyline(int[][] buildings)
{
List <int[]> buildings2 = new List <int[]>(buildings.Length * 2);
foreach (var b in buildings)
{
buildings2.Add(new int[] { b[0], -b[2] });
buildings2.Add(new int[] { b[1], b[2] });
}
buildings2.Sort((x, y) =>
{
var c = x[0].CompareTo(y[0]);
if (c == 0)
{
c = x[1].CompareTo(y[1]);
}
return(c);
});
List <IList <int> > ans = new List <IList <int> >();
DuplicatedSortedTree <int> heap = new DuplicatedSortedTree <int>();
int prev = 0;
foreach (var b in buildings2)
{
if (b[1] < 0)
{
heap.Add(-b[1]);
}
else
{
heap.Remove(b[1]);
}
int max = 0;
if (heap.Count > 0)
{
max = heap.Max;
}
if (max != prev)
{
ans.Add(new List <int> {
b[0], max
});
}
prev = max;
}
return(ans);
}