AVL tree/C sharp

From Rosetta Code

Code[edit]

 
// Finite Ordered Sets - 4State - Balanced
 
using System;
using System.Collections.Generic;
 
public enum Direction { FromLeft, FromRight };
 
public enum State { Header, LeftHigh, Balanced, RightHigh };
 
public enum SetOperation
{
Union,
Intersection,
SymmetricDifference,
Difference,
Equality,
Inequality,
Subset,
Superset
}
 
public class Node
{
public Node Left;
public Node Right;
public Node Parent;
public State Balance;
 
public Node()
{
Left = this;
Right = this;
Parent = null;
Balance = State.Header;
}
 
public Node(Node p)
{
Left = null;
Right = null;
Parent = p;
Balance = State.Balanced;
}
 
public bool IsHeader
{ get { return Balance == State.Header; } }
}
 
public class SetNode<T> : Node
{
public T Data;
 
public SetNode() { }
 
public SetNode(T dataType, Node Parent) : base(Parent)
{
Data = dataType;
}
 
public override int GetHashCode()
{
return Data.GetHashCode();
}
}
 
class Utility // Nongeneric Tree Balancing
{
static void RotateLeft(ref Node Root)
{
Node Parent = Root.Parent;
Node x = Root.Right;
 
Root.Parent = x;
x.Parent = Parent;
if (x.Left != null) x.Left.Parent = Root;
 
Root.Right = x.Left;
x.Left = Root;
Root = x;
}
 
static void RotateRight(ref Node Root)
{
Node Parent = Root.Parent;
Node x = Root.Left;
 
Root.Parent = x;
x.Parent = Parent;
if (x.Right != null) x.Right.Parent = Root;
 
Root.Left = x.Right;
x.Right = Root;
Root = x;
}
 
static void BalanceLeft(ref Node Root)
{
Node Left = Root.Left;
 
switch (Left.Balance)
{
case State.LeftHigh:
Root.Balance = State.Balanced;
Left.Balance = State.Balanced;
RotateRight(ref Root);
break;
 
case State.RightHigh:
{
Node subRight = Left.Right;
switch (subRight.Balance)
{
case State.Balanced:
Root.Balance = State.Balanced;
Left.Balance = State.Balanced;
break;
 
case State.RightHigh:
Root.Balance = State.Balanced;
Left.Balance = State.LeftHigh;
break;
 
case State.LeftHigh:
Root.Balance = State.RightHigh;
Left.Balance = State.Balanced;
break;
}
subRight.Balance = State.Balanced;
RotateLeft(ref Left);
Root.Left = Left;
RotateRight(ref Root);
}
break;
 
case State.Balanced:
Root.Balance = State.LeftHigh;
Left.Balance = State.RightHigh;
RotateRight(ref Root);
break;
}
}
 
static void BalanceRight(ref Node Root)
{
Node Right = Root.Right;
 
switch (Right.Balance)
{
case State.RightHigh:
Root.Balance = State.Balanced;
Right.Balance = State.Balanced;
RotateLeft(ref Root);
break;
 
case State.LeftHigh:
{
Node subLeft = Right.Left; // Left Subtree of Right
switch (subLeft.Balance)
{
case State.Balanced:
Root.Balance = State.Balanced;
Right.Balance = State.Balanced;
break;
 
case State.LeftHigh:
Root.Balance = State.Balanced;
Right.Balance = State.RightHigh;
break;
 
case State.RightHigh:
Root.Balance = State.LeftHigh;
Right.Balance = State.Balanced;
break;
}
subLeft.Balance = State.Balanced;
RotateRight(ref Right);
Root.Right = Right;
RotateLeft(ref Root);
}
break;
 
case State.Balanced:
Root.Balance = State.RightHigh;
Right.Balance = State.LeftHigh;
RotateLeft(ref Root);
break;
}
}
 
public static void BalanceSet(Node Root, Direction From)
{
bool Taller = true;
 
while (Taller)
{
Node Parent = Root.Parent;
Direction NextFrom = (Parent.Left == Root) ? Direction.FromLeft : Direction.FromRight;
 
if (From == Direction.FromLeft)
{
switch (Root.Balance)
{
case State.LeftHigh:
if (Parent.IsHeader)
BalanceLeft(ref Parent.Parent);
else if (Parent.Left == Root)
BalanceLeft(ref Parent.Left);
else
BalanceLeft(ref Parent.Right);
Taller = false;
break;
 
case State.Balanced:
Root.Balance = State.LeftHigh;
Taller = true;
break;
 
case State.RightHigh:
Root.Balance = State.Balanced;
Taller = false;
break;
}
}
else
{
switch (Root.Balance)
{
case State.LeftHigh:
Root.Balance = State.Balanced;
Taller = false;
break;
 
case State.Balanced:
Root.Balance = State.RightHigh;
Taller = true;
break;
 
case State.RightHigh:
if (Parent.IsHeader)
BalanceRight(ref Parent.Parent);
else if (Parent.Left == Root)
BalanceRight(ref Parent.Left);
else
BalanceRight(ref Parent.Right);
Taller = false;
break;
}
}
 
if (Taller) // skip up a level
{
if (Parent.IsHeader)
Taller = false;
else
{
Root = Parent;
From = NextFrom;
}
}
}
}
 
public static void BalanceSetRemove(Node Root, Direction From)
{
if (Root.IsHeader) return;
 
bool Shorter = true;
 
while (Shorter)
{
Node Parent = Root.Parent;
Direction NextFrom = (Parent.Left == Root) ? Direction.FromLeft : Direction.FromRight;
 
if (From == Direction.FromLeft)
{
switch (Root.Balance)
{
case State.LeftHigh:
Root.Balance = State.Balanced;
Shorter = true;
break;
 
case State.Balanced:
Root.Balance = State.RightHigh;
Shorter = false;
break;
 
case State.RightHigh:
if (Root.Right.Balance == State.Balanced)
Shorter = false;
else
Shorter = true;
if (Parent.IsHeader)
BalanceRight(ref Parent.Parent);
else if (Parent.Left == Root)
BalanceRight(ref Parent.Left);
else
BalanceRight(ref Parent.Right);
break;
}
}
else
{
switch (Root.Balance)
{
case State.RightHigh:
Root.Balance = State.Balanced;
Shorter = true;
break;
 
case State.Balanced:
Root.Balance = State.LeftHigh;
Shorter = false;
break;
 
case State.LeftHigh:
if (Root.Left.Balance == State.Balanced)
Shorter = false;
else
Shorter = true;
if (Parent.IsHeader)
BalanceLeft(ref Parent.Parent);
else if (Parent.Left == Root)
BalanceLeft(ref Parent.Left);
else
BalanceLeft(ref Parent.Right);
break;
}
}
 
if (Shorter)
{
if (Parent.IsHeader)
Shorter = false;
else
{
From = NextFrom;
Root = Parent;
}
}
}
}
 
public static Node PreviousItem(Node Node)
{
if (Node.IsHeader) { return Node.Right; }
 
if (Node.Left != null)
{
Node = Node.Left;
while (Node.Right != null) Node = Node.Right;
}
else
{
Node y = Node.Parent;
if (y.IsHeader) return y;
while (Node == y.Left) { Node = y; y = y.Parent; }
Node = y;
}
return Node;
}
 
public static Node NextItem(Node Node)
{
if (Node.IsHeader) return Node.Left;
 
if (Node.Right != null)
{
Node = Node.Right;
while (Node.Left != null) Node = Node.Left;
}
else
{
Node y = Node.Parent;
if (y.IsHeader) return y;
while (Node == y.Right) { Node = y; y = y.Parent; }
Node = y;
}
return Node;
}
 
public static ulong Depth(Node Root)
{
if (Root != null)
{
ulong Left = Root.Left != null ? Depth(Root.Left) : 0;
ulong Right = Root.Right != null ? Depth(Root.Right) : 0;
return Left < Right ? Right + 1 : Left + 1;
}
else
return 0;
}
 
static void SwapNodeReference(ref Node First,
ref Node Second)
{ Node Temporary = First; First = Second; Second = Temporary; }
 
public static void SwapNodes(Node A, Node B)
{
if (B == A.Left)
{
if (B.Left != null) B.Left.Parent = A;
if (B.Right != null) B.Right.Parent = A;
 
if (A.Right != null) A.Right.Parent = B;
 
if (!A.Parent.IsHeader)
{
if (A.Parent.Left == A)
A.Parent.Left = B;
else
A.Parent.Right = B;
}
else A.Parent.Parent = B;
 
B.Parent = A.Parent;
A.Parent = B;
 
A.Left = B.Left;
B.Left = A;
 
SwapNodeReference(ref A.Right, ref B.Right);
}
else if (B == A.Right)
{
if (B.Right != null) B.Right.Parent = A;
if (B.Left != null) B.Left.Parent = A;
 
if (A.Left != null) A.Left.Parent = B;
 
if (!A.Parent.IsHeader)
{
if (A.Parent.Left == A)
A.Parent.Left = B;
else
A.Parent.Right = B;
}
else A.Parent.Parent = B;
 
B.Parent = A.Parent;
A.Parent = B;
 
A.Right = B.Right;
B.Right = A;
 
SwapNodeReference(ref A.Left, ref B.Left);
}
else if (A == B.Left)
{
if (A.Left != null) A.Left.Parent = B;
if (A.Right != null) A.Right.Parent = B;
 
if (B.Right != null) B.Right.Parent = A;
 
if (!B.Parent.IsHeader)
{
if (B.Parent.Left == B)
B.Parent.Left = A;
else
B.Parent.Right = A;
}
else B.Parent.Parent = A;
 
A.Parent = B.Parent;
B.Parent = A;
 
B.Left = A.Left;
A.Left = B;
 
SwapNodeReference(ref A.Right, ref B.Right);
}
else if (A == B.Right)
{
if (A.Right != null) A.Right.Parent = B;
if (A.Left != null) A.Left.Parent = B;
 
if (B.Left != null) B.Left.Parent = A;
 
if (!B.Parent.IsHeader)
{
if (B.Parent.Left == B)
B.Parent.Left = A;
else
B.Parent.Right = A;
}
else B.Parent.Parent = A;
 
A.Parent = B.Parent;
B.Parent = A;
 
B.Right = A.Right;
A.Right = B;
 
SwapNodeReference(ref A.Left, ref B.Left);
}
else
{
if (A.Parent == B.Parent)
SwapNodeReference(ref A.Parent.Left, ref A.Parent.Right);
else
{
if (!A.Parent.IsHeader)
{
if (A.Parent.Left == A)
A.Parent.Left = B;
else
A.Parent.Right = B;
}
else A.Parent.Parent = B;
 
if (!B.Parent.IsHeader)
{
if (B.Parent.Left == B)
B.Parent.Left = A;
else
B.Parent.Right = A;
}
else B.Parent.Parent = A;
}
 
if (B.Left != null) B.Left.Parent = A;
if (B.Right != null) B.Right.Parent = A;
 
if (A.Left != null) A.Left.Parent = B;
if (A.Right != null) A.Right.Parent = B;
 
SwapNodeReference(ref A.Left, ref B.Left);
SwapNodeReference(ref A.Right, ref B.Right);
SwapNodeReference(ref A.Parent, ref B.Parent);
}
 
State Balance = A.Balance;
A.Balance = B.Balance;
B.Balance = Balance;
}
}
 
public struct SetEntry<T> : IEnumerator<T>
{
public SetEntry(Node N) { _Node = N; }
 
public T Value
{
get
{
return ((SetNode<T>)_Node).Data;
}
}
 
public bool IsEnd { get { return _Node.IsHeader; } }
 
public bool MoveNext()
{
_Node = Utility.NextItem(_Node);
return _Node.IsHeader ? false : true;
}
 
public bool MovePrevious()
{
_Node = Utility.PreviousItem(_Node);
return _Node.IsHeader ? false : true;
}
 
public static SetEntry<T> operator ++(SetEntry<T> entry)
{
entry._Node = Utility.NextItem(entry._Node);
return entry;
}
 
public static SetEntry<T> operator --(SetEntry<T> entry)
{
entry._Node = Utility.PreviousItem(entry._Node);
return entry;
}
 
public void Reset()
{
while (!MoveNext()) ;
}
 
object System.Collections.IEnumerator.Current
{ get { return ((SetNode<T>)_Node).Data; } }
 
T IEnumerator<T>.Current
{ get { return ((SetNode<T>)_Node).Data; } }
 
public static bool operator ==(SetEntry<T> x, SetEntry<T> y) { return x._Node == y._Node; }
public static bool operator !=(SetEntry<T> x, SetEntry<T> y) { return x._Node != y._Node; }
 
public override bool Equals(object o) { return _Node == ((SetEntry<T>)o)._Node; }
 
public override int GetHashCode() { return _Node.GetHashCode(); }
 
public static SetEntry<T> operator +(SetEntry<T> C, ulong Increment)
{
SetEntry<T> Result = new SetEntry<T>(C._Node);
for (ulong i = 0; i < Increment; i++) ++Result;
return Result;
}
 
public static SetEntry<T> operator +(ulong Increment, SetEntry<T> C)
{
SetEntry<T> Result = new SetEntry<T>(C._Node);
for (ulong i = 0; i < Increment; i++) ++Result;
return Result;
}
 
public static SetEntry<T> operator -(SetEntry<T> C, ulong Decrement)
{
SetEntry<T> Result = new SetEntry<T>(C._Node);
for (ulong i = 0; i < Decrement; i++) --Result;
return Result;
}
 
public override string ToString()
{
return Value.ToString();
}
 
public void Dispose() { }
 
public Node _Node;
}
 
class Set<T> : IEnumerable<T>
{
IComparer<T> Comparer;
Node Header;
ulong Nodes;
 
//*** Constructors ***
 
public Set()
{
Comparer = Comparer<T>.Default;
Header = new Node();
Nodes = 0;
}
 
public Set(IComparer<T> c)
{
Comparer = c;
Header = new Node();
Nodes = 0;
}
 
//*** Properties ***
 
SetNode<T> Root
{
get { return (SetNode<T>)Header.Parent; }
set { Header.Parent = value; }
}
 
Node LeftMost
{
get { return Header.Left; }
set { Header.Left = value; }
}
 
Node RightMost
{
get { return Header.Right; }
set { Header.Right = value; }
}
 
public SetEntry<T> Begin
{ get { return new SetEntry<T>(Header.Left); } }
 
public SetEntry<T> End
{ get { return new SetEntry<T>(Header); } }
 
public ulong Length { get { return Nodes; } }
 
public ulong Depth { get { return Utility.Depth(Root); } }
 
//*** Operators ***
 
public bool this[T key] { get { return Search(key); } }
 
public static Set<T> operator +(Set<T> set, T t)
{
set.Add(t); return set;
}
 
public static Set<T> operator -(Set<T> set, T t)
{
set.Remove(t); return set;
}
 
public static Set<T> operator |(Set<T> A, Set<T> B)
{
Set<T> U = new Set<T>(A.Comparer);
CombineSets(A, B, U, SetOperation.Union);
return U;
}
 
public static Set<T> operator &(Set<T> A, Set<T> B)
{
Set<T> I = new Set<T>(A.Comparer);
CombineSets(A, B, I, SetOperation.Intersection);
return I;
}
 
public static Set<T> operator ^(Set<T> A, Set<T> B)
{
Set<T> S = new Set<T>(A.Comparer);
CombineSets(A, B, S, SetOperation.SymmetricDifference);
return S;
}
 
public static Set<T> operator -(Set<T> A, Set<T> B)
{
Set<T> S = new Set<T>(A.Comparer);
CombineSets(A, B, S, SetOperation.Difference);
return S;
}
 
public static bool operator ==(Set<T> A, Set<T> B)
{
return CheckSets(A, B, SetOperation.Equality);
}
 
public static bool operator !=(Set<T> A, Set<T> B)
{
return CheckSets(A, B, SetOperation.Inequality);
}
 
public override bool Equals(object o)
{
return CheckSets(this, (Set<T>)o, SetOperation.Equality);
}
 
 
//*** Methods ***
 
public void Add(T key)
{
if (Root == null)
{
Root = new SetNode<T>(key, Header);
LeftMost = RightMost = Root;
}
else
{
SetNode<T> Search = Root;
for (; ; )
{
int Compare = Comparer.Compare(key, Search.Data);
 
if (Compare == 0) // Item Exists
throw new EntryAlreadyExistsException();
 
else if (Compare < 0)
{
if (Search.Left != null)
Search = (SetNode<T>)Search.Left;
else
{
Search.Left = new SetNode<T>(key, Search);
if (LeftMost == Search) LeftMost = (SetNode<T>)Search.Left;
Utility.BalanceSet(Search, Direction.FromLeft);
Nodes++;
break;
}
}
 
else
{
if (Search.Right != null)
Search = (SetNode<T>)Search.Right;
else
{
Search.Right = new SetNode<T>(key, Search);
if (RightMost == Search) RightMost = (SetNode<T>)Search.Right;
Utility.BalanceSet(Search, Direction.FromRight);
Nodes++;
break;
}
}
}
}
}
 
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{ return new SetEntry<T>(Header); }
 
IEnumerator<T> IEnumerable<T>.GetEnumerator()
{ return new SetEntry<T>(Header); }
 
public override int GetHashCode()
{
return GetHashCode((SetNode<T>)Header.Parent);
}
 
int GetHashCode(SetNode<T> Root)
{
if (Root != null)
{
int HashCode = Root.GetHashCode();
 
if (Root.Left != null)
HashCode += GetHashCode((SetNode<T>)Root.Left);
 
if (Root.Right != null)
HashCode += GetHashCode((SetNode<T>)Root.Right);
 
return HashCode;
}
 
return 0;
}
 
 
public void Remove(T key)
{
SetNode<T> root = Root;
 
for (; ; )
{
if (root == null)
throw new EntryNotFoundException();
 
int Compare = Comparer.Compare(key, root.Data);
 
if (Compare < 0)
root = (SetNode<T>)root.Left;
 
else if (Compare > 0)
root = (SetNode<T>)root.Right;
 
else // Item is found
{
if (root.Left != null && root.Right != null)
{
SetNode<T> replace = (SetNode<T>)root.Left;
while (replace.Right != null) replace = (SetNode<T>)replace.Right;
Utility.SwapNodes(root, replace);
}
 
SetNode<T> Parent = (SetNode<T>)root.Parent;
 
Direction From = (Parent.Left == root) ? Direction.FromLeft : Direction.FromRight;
 
if (LeftMost == root)
{
SetEntry<T> e = new SetEntry<T>(root); e.MoveNext();
 
if (e._Node.IsHeader)
{ LeftMost = Header; RightMost = Header; }
else
LeftMost = e._Node;
}
else if (RightMost == root)
{
SetEntry<T> e = new SetEntry<T>(root); e.MovePrevious();
 
if (e._Node.IsHeader)
{ LeftMost = Header; RightMost = Header; }
else
RightMost = e._Node;
}
 
if (root.Left == null)
{
if (Parent == Header)
Header.Parent = root.Right;
else if (Parent.Left == root)
Parent.Left = root.Right;
else
Parent.Right = root.Right;
 
if (root.Right != null) root.Right.Parent = Parent;
}
else
{
if (Parent == Header)
Header.Parent = root.Left;
else if (Parent.Left == root)
Parent.Left = root.Left;
else
Parent.Right = root.Left;
 
if (root.Left != null) root.Left.Parent = Parent;
}
 
Utility.BalanceSetRemove(Parent, From);
Nodes--;
break;
}
}
}
 
public bool Search(T key)
{
if (Root == null)
return false;
else
{
SetNode<T> Search = Root;
 
do
{
int Result = Comparer.Compare(key, Search.Data);
 
if (Result < 0) Search = (SetNode<T>)Search.Left;
 
else if (Result > 0) Search = (SetNode<T>)Search.Right;
 
else break;
 
} while (Search != null);
 
if (Search == null)
return false;
else
return true;
}
}
 
public override string ToString()
{
string StringOut = "{";
 
SetEntry<T> start = Begin;
SetEntry<T> end = End;
SetEntry<T> last = End - 1;
 
while (start != end)
{
string new_StringOut = start.Value.ToString();
if (start != last) new_StringOut = new_StringOut + ",";
StringOut = StringOut + new_StringOut;
++start;
}
 
StringOut = StringOut + "}";
return StringOut;
}
 
public void Validate()
{
if (Nodes == 0 || Root == null)
{
if (Nodes != 0) { throw new InvalidEmptyTreeException(); }
if (Root != null) { throw new InvalidEmptyTreeException(); }
if (LeftMost != Header) { throw new InvalidEndItemException(); }
if (RightMost != Header) { throw new InvalidEndItemException(); }
}
 
Validate(Root);
 
if (Root != null)
{
SetNode<T> x = Root;
while (x.Left != null) x = (SetNode<T>)x.Left;
 
if (LeftMost != x) throw new InvalidEndItemException();
 
SetNode<T> y = Root;
while (y.Right != null) y = (SetNode<T>)y.Right;
 
if (RightMost != y) throw new InvalidEndItemException();
}
}
 
void Validate(SetNode<T> root)
{
if (root == null) return;
 
if (root.Left != null)
{
SetNode<T> Left = (SetNode<T>)root.Left;
 
if (Comparer.Compare(Left.Data, root.Data) >= 0)
throw new OutOfKeyOrderException();
 
if (Left.Parent != root)
throw new TreeInvalidParentException();
 
Validate((SetNode<T>)root.Left);
}
 
if (root.Right != null)
{
SetNode<T> Right = (SetNode<T>)root.Right;
 
if (Comparer.Compare(Right.Data, root.Data) <= 0)
throw new OutOfKeyOrderException();
 
if (Right.Parent != root)
throw new TreeInvalidParentException();
 
Validate((SetNode<T>)root.Right);
}
 
ulong depth_Left = root.Left != null ? Utility.Depth(root.Left) : 0;
ulong depth_Right = root.Right != null ? Utility.Depth(root.Right) : 0;
 
if (depth_Left > depth_Right && depth_Left - depth_Right > 2)
throw new TreeOutOfBalanceException();
 
if (depth_Left < depth_Right && depth_Right - depth_Left > 2)
throw new TreeOutOfBalanceException();
}
 
public static void CombineSets(Set<T> A,
Set<T> B,
Set<T> R,
SetOperation operation)
{
IComparer<T> TComparer = R.Comparer;
SetEntry<T> First1 = A.Begin;
SetEntry<T> Last1 = A.End;
SetEntry<T> First2 = B.Begin;
SetEntry<T> Last2 = B.End;
 
switch (operation)
{
case SetOperation.Union:
while (First1 != Last1 && First2 != Last2)
{
int Order = TComparer.Compare(First1.Value, First2.Value);
 
if (Order < 0)
{
R.Add(First1.Value);
First1.MoveNext();
}
 
else if (Order > 0)
{
R.Add(First2.Value);
First2.MoveNext();
}
 
else
{
R.Add(First1.Value);
First1.MoveNext();
First2.MoveNext();
}
}
while (First1 != Last1)
{
R.Add(First1.Value);
First1.MoveNext();
}
while (First2 != Last2)
{
R.Add(First2.Value);
First2.MoveNext();
}
return;
 
case SetOperation.Intersection:
while (First1 != Last1 && First2 != Last2)
{
int Order = TComparer.Compare(First1.Value, First2.Value);
 
if (Order < 0)
First1.MoveNext();
 
else if (Order > 0)
First2.MoveNext();
 
else
{
R.Add(First1.Value);
First1.MoveNext();
First2.MoveNext();
}
}
return;
 
case SetOperation.SymmetricDifference:
while (First1 != Last1 && First2 != Last2)
{
int Order = TComparer.Compare(First1.Value, First2.Value);
 
if (Order < 0)
{
R.Add(First1.Value);
First1.MoveNext();
}
 
else if (Order > 0)
{
R.Add(First2.Value);
First2.MoveNext();
}
 
else
{ First1.MoveNext(); First2.MoveNext(); }
}
 
while (First1 != Last1)
{
R.Add(First1.Value);
First1.MoveNext();
}
 
while (First2 != Last2)
{
R.Add(First2.Value);
First2.MoveNext();
}
return;
 
case SetOperation.Difference:
while (First1 != Last1 && First2 != Last2)
{
int Order = TComparer.Compare(First1.Value, First2.Value);
 
if (Order < 0)
{
R.Add(First1.Value);
First1.MoveNext();
}
 
else if (Order > 0)
{
R.Add(First1.Value);
First1.MoveNext();
First2.MoveNext();
}
 
else
{ First1.MoveNext(); First2.MoveNext(); }
}
 
while (First1 != Last1)
{
R.Add(First1.Value);
First1.MoveNext();
}
return;
}
 
throw new InvalidSetOperationException();
}
 
public static bool CheckSets(Set<T> A,
Set<T> B,
SetOperation operation)
{
IComparer<T> TComparer = A.Comparer;
SetEntry<T> First1 = A.Begin;
SetEntry<T> Last1 = A.End;
SetEntry<T> First2 = B.Begin;
SetEntry<T> Last2 = B.End;
 
switch (operation)
{
case SetOperation.Equality:
case SetOperation.Inequality:
{
bool Equals = true;
 
while (First1 != Last1 && First2 != Last2)
{
if (TComparer.Compare(First1.Value, First2.Value) == 0)
{ First1.MoveNext(); First2.MoveNext(); }
else
{ Equals = false; break; }
}
 
if (Equals)
{
if (First1 != Last1) Equals = false;
if (First2 != Last2) Equals = false;
}
 
if (operation == SetOperation.Equality)
return Equals;
else
return !Equals;
}
 
case SetOperation.Subset:
case SetOperation.Superset:
{
bool Subset = true;
 
while (First1 != Last1 && First2 != Last2)
{
int Order = TComparer.Compare(First1.Value, First2.Value);
 
if (Order < 0)
{ Subset = false; break; }
 
else if (Order > 0)
First2.MoveNext();
 
else
{ First1.MoveNext(); First2.MoveNext(); }
}
 
if (Subset)
if (First1 != Last1) Subset = false;
 
if (operation == SetOperation.Subset)
return Subset;
else
return !Subset;
}
}
 
throw new InvalidSetOperationException();
}
}
 
public class EntryNotFoundException : Exception
{
static String message = "The requested entry could not be located in the specified collection.";
 
public EntryNotFoundException() : base(message) { }
}
 
public class EntryAlreadyExistsException : Exception
{
static String message = "The requested entry already resides in the collection.";
 
public EntryAlreadyExistsException() : base(message) { }
}
 
public class InvalidEndItemException : Exception
{
static String message = "The validation routines detected that the end item of a tree is invalid.";
 
public InvalidEndItemException() : base(message) { }
}
 
public class InvalidEmptyTreeException : Exception
{
static String message = "The validation routines detected that an empty tree is invalid.";
 
public InvalidEmptyTreeException() : base(message) { }
}
 
public class OutOfKeyOrderException : Exception
{
static String message = "A trees was found to be out of key order.";
 
public OutOfKeyOrderException() : base(message) { }
}
 
public class TreeInvalidParentException : Exception
{
static String message = "The validation routines detected that the Parent structure of a tree is invalid.";
 
public TreeInvalidParentException() : base(message) { }
}
 
public class TreeOutOfBalanceException : Exception
{
static String message = "The validation routines detected that the tree is out of State.";
 
public TreeOutOfBalanceException() : base(message) { }
}
 
public class InvalidSetOperationException : Exception
{
static String message = "An invalid set operation was requested.";
 
public InvalidSetOperationException() : base(message) { }
}
 
class Program
{
static void Main()
{
Set<string> s = new Set<string>() {"S0","S1","S2","S3","S4",
"S5","S6","S7","S8","S9"};
 
Console.WriteLine("Depth = {0}", s.Depth);
 
s.Validate();
 
for (int i = 0; i < 10; i += 2)
s.Remove("S" + i.ToString());
 
Console.WriteLine("Depth = {0}", s.Depth);
 
s.Validate();
 
Console.WriteLine("{0}", s);
 
Set<int> A = new Set<int>() { 1, 3, 5, 7 };
Set<int> B = new Set<int>() { 2, 4, 6, 8 };
 
Set<int> U = A | B;
 
Console.WriteLine("{0} | {1} == {2}", A, B, U);
}
}