private void FillVoxelPoint(Point3D voxelPoint)
{
var bot = _scene.GetFirstBot();
var botVector = Vector3D.FromPoint(bot.Current);
var voxelVector = Vector3D.FromPoint(voxelPoint);
var dsuIndex = GetPointDSUIndex(voxelPoint);
if (voxelPoint.Y == 0)
{
// foreach (var point in FilledAdjacent(voxelPoint))
// {
// var p = GetPointDSUIndex(point);
// _dsu.Union(p, dsuIndex);
// }
_dsu.Union(0, dsuIndex);
}
else
{
var adjacentFilled = FilledAdjacent(voxelPoint).ToList();
if (adjacentFilled.Count > 0)
{
foreach (var point in adjacentFilled)
{
var p = GetPointDSUIndex(point);
_dsu.Union(p, dsuIndex);
}
}
else
{
if (_scene.SceneState.HarmonicsMode == HarmonicsMode.Grounded)
{
ApplyCommand(new FlipCommand());
}
}
}
_voxelsFilled += 1;
ApplyCommand(new FillCommand(voxelVector - botVector));
if (_voxelsFilled == _dsu.SizeOf(0) - 2)
{
if (_scene.SceneState.HarmonicsMode == HarmonicsMode.Floating)
{
ApplyCommand(new FlipCommand());
}
}
else
{
if (_scene.SceneState.HarmonicsMode == HarmonicsMode.Grounded)
{
ApplyCommand(new FlipCommand());
}
}
}
static void Main()
{
string[] lines = File.ReadAllLines("dsu.in");
int n = int.Parse(lines[0]);
DSU dsu = new DSU();
for (int i = 1; i <= n; ++i)
dsu.AddSingleItem(i);
StreamWriter sw = new StreamWriter("dsu.out");
foreach (string s in lines.Skip(1))
{
string[] parts = s.Split(' ');
if (parts[0] == "union")
{
int a = int.Parse(parts[1]) - 1,
b = int.Parse(parts[2]) - 1;
dsu.Union(a,b);
}
else
if (parts[0] == "get")
{
int a = int.Parse(parts[1]) - 1;
DSU.DsuSet x = dsu.Get(a);
sw.WriteLine("{0} {1} {2}", x.Min, x.Max, x.Count);
}
}
sw.Close();
}
public IList <int> NumIslands2(int rows, int cols, int[,] positions)
{
var dsu = new DSU(rows * cols);
var result = new List <int>();
int GetIndx(int r, int c) => r * cols + c;
for (var i = 0; i < positions.GetLength(0); i++)
{
var r = positions[i, 0];
var c = positions[i, 1];
var indx = GetIndx(r, c);
dsu.Set(indx);
var up = GetIndx(r - 1, c);
if (r - 1 >= 0 && dsu.IsSet(up))
{
dsu.Union(indx, up);
}
var down = GetIndx(r + 1, c);
if (r + 1 < rows && dsu.IsSet(down))
{
dsu.Union(indx, down);
}
var left = GetIndx(r, c - 1);
if (c - 1 >= 0 && dsu.IsSet(left))
{
dsu.Union(indx, left);
}
var right = GetIndx(r, c + 1);
if (c + 1 < cols && dsu.IsSet(right))
{
dsu.Union(indx, right);
}
result.Add(dsu.GetCount());
}
return(result);
}
/// <summary>
/// Nov. 19, 2020
/// Union find algorithm
/// study code
/// https://leetcode.com/problems/sentence-similarity-ii/solution/
/// Time complexity:
/// Time Complexity: O(N log P + P), where N is the maximum length of words1 and words2,
/// and P is the length of pairs. If we used union-by-rank, this complexity improves to
/// O(N * a(P) + P), close to O(N + P), where α is the Inverse-Ackermann function.
/// </summary>
/// <param name="words1"></param>
/// <param name="words2"></param>
/// <param name="pairs"></param>
/// <returns></returns>
public bool AreSentencesSimilarTwo(string[] words1, string[] words2, IList <IList <string> > pairs)
{
var length1 = words1.Length;
var length2 = words2.Length;
var pLength = pairs.Count;
if (length1 != length2)
{
return(false);
}
// index -> indexMap better name?
var indexMap = new Dictionary <string, int>();
int count = 0;
var dsu = new DSU(2 * pLength);
foreach (var pair in pairs)
{
// go through two words in one pair
foreach (var p in pair)
{
if (!indexMap.ContainsKey(p))
{
indexMap.Add(p, count++);
}
}
dsu.Union(indexMap[pair[0]], indexMap[pair[1]]);
}
for (int i = 0; i < length1; ++i)
{
var w1 = words1[i];
var w2 = words2[i];
if (w1.CompareTo(w2) == 0)
{
continue;
}
if (!indexMap.ContainsKey(w1) ||
!indexMap.ContainsKey(w2) ||
dsu.Find(indexMap[w1]) != dsu.Find(indexMap[w2]))
{
return(false);
}
}
return(true);
}
public int[] FindRedundantConnection2(int[][] edges)
{
DSU = new DSU(edges.Length + 1);
foreach (int[] edge in edges)
{
if (DSU.Union(edge[0], edge[1]))
{
return(edge);
}
}
return(edges[0]);
}
private int[] FindRedundantConnection(int[][] edges)
{
DSU dsu = new DSU(edges.Length);
foreach (int[] edge in edges)
{
if (!dsu.Union(edge[0], edge[1]))
{
return(edge);
}
}
throw new ArgumentException("Invalid argument");
}
public int RemoveStones(int[][] stones)
{
var dsu = new DSU(20000);
foreach (var stone in stones)
{
dsu.Union(stone[0], stone[1] + 10000);
}
var seen = new HashSet <int>();
foreach (var stone in stones)
{
seen.Add(dsu.Find(stone[0]));
}
return(stones.Length - seen.Count);
}
private int MinCostToConnectNodes(int N, int[][] connections)
{
Array.Sort(connections, (a, b) => a[2] - b[2]);
DSU dsu = new DSU(N + 1);
int cost = 0;
foreach (int[] arr in connections)
{
if (!dsu.Union(arr[0], arr[1]))
{
cost += arr[2];
}
}
return(dsu.Count == 2 ? cost : -1);
}
public IList <IList <string> > AccountsMerge(IList <IList <string> > accounts)
{
EmailToId = new Dictionary <string, int>();
EmailToName = new Dictionary <string, string>();
foreach (var account in accounts)
{
if (account.Count < 2)
{
continue;
}
var name = account[0];
for (var i = 1; i < account.Count; i++)
{
if (!EmailToId.ContainsKey(account[i]))
{
var id = EmailToId.Count;
EmailToId[account[i]] = id;
EmailToName[account[i]] = name;
}
}
}
var totalAccounts = EmailToId.Count;
DSU = new DSU(totalAccounts);
foreach (var account in accounts)
{
// var name = account[0];
for (var i = 1; i < account.Count - 1; i++)
{
var id1 = EmailToId[account[i]];
var id2 = EmailToId[account[i + 1]];
if (id1 != id2)
{
DSU.Union(id1, id2);
}
}
}
var result = new Dictionary <int, List <string> >();
foreach (var email in EmailToName.Keys)
{
int index = DSU.Find(EmailToId[email]);
if (result.TryGetValue(index, out var list))
{
list.Add(email);
}
else
{
result[index] = new List <string> {
email
};
}
}
foreach (var emails in result.Values)
{
emails.Sort((x, y) =>
{
var i = 0;
while (i < x.Length && i < y.Length)
{
if (x[i] != y[i])
{
return(x[i].CompareTo(y[i]));
}
i++;
}
return(x.Length.CompareTo(y.Length));
});
emails.Insert(0, EmailToName[emails[0]]);
}
return(result.Values.ToList <IList <string> >());
}