public static int GetDegree(this IBinaryTreeNode node)
{
Contract.Requires <ArgumentNullException>(node != null);
Contract.Ensures(Contract.Result <int>() >= 0 && Contract.Result <int>() <= 2);
if (SentinelEx.NotEqualNull(node.LeftChild))
{
if (SentinelEx.NotEqualNull(node.RightChild))
{
return(2);
}
else
{
return(1);
}
}
else if (SentinelEx.NotEqualNull(node.RightChild))
{
return(1);
}
else
{
return(0);
}
}
private static IEnumerable <Tuple <IBinaryTreeNode, TLevel> > LevelOrderTraverse <TLevel>(
IBinaryTreeNode partialroot,
TLevel seed,
Func <TLevel, IBinaryTreeNode, TLevel> leftlevelfunc,
Func <TLevel, IBinaryTreeNode, TLevel> rightlevelfunc)
{
var queue = new Queue <Tuple <IBinaryTreeNode, TLevel> >();
queue.Enqueue(new Tuple <IBinaryTreeNode, TLevel>(partialroot, seed));
while (queue.Count > 0)
{
var current = queue.Dequeue();
if (!SentinelEx.EqualNull(current.Item1.LeftChild))
{
queue.Enqueue(new Tuple <IBinaryTreeNode, TLevel>(current.Item1.LeftChild,
leftlevelfunc == null ? current.Item2 : leftlevelfunc(current.Item2, partialroot)));
}
if (!SentinelEx.EqualNull(current.Item1.RightChild))
{
queue.Enqueue(new Tuple <IBinaryTreeNode, TLevel>(current.Item1.RightChild,
rightlevelfunc == null ? current.Item2 : rightlevelfunc(current.Item2, partialroot)));
}
yield return(current);
}
}
private static IEnumerable <Tuple <IMultiwayTreeNode, TLevel> > LevelOrderTraverse <TLevel>(
IMultiwayTreeNode partialroot,
TLevel seed,
Func <TLevel, IMultiwayTreeNode, int, TLevel> levelfunc)
{
var queue = new Queue <Tuple <IMultiwayTreeNode, TLevel> >();
queue.Enqueue(new Tuple <IMultiwayTreeNode, TLevel>(partialroot, seed));
int index;
while (queue.Count > 0)
{
index = 0;
var current = queue.Dequeue();
if (SentinelEx.NotEqualNull(current.Item1.Children))
{
foreach (var node in current.Item1.Children)
{
queue.Enqueue(new Tuple <IMultiwayTreeNode, TLevel>(node,
levelfunc == null ? current.Item2 : levelfunc(current.Item2, partialroot, index++)));
}
}
yield return(current);
}
}
protected override bool MoveNextInternal()
{
if (SentinelEx.NotEqualNull(_current.RightChild))
{
_stack.Push(_current);
_current = _current.RightChild as TNode;
while (SentinelEx.NotEqualNull(_current.LeftChild))
{
_stack.Push(_current);
_current = _current.LeftChild as TNode;
}
return(true);
}
else
{
while (_stack.Count > 0 && _stack.Peek().RightChild == _current)
{
_current = _stack.Pop(); //向上找到右行点
}
if (_stack.Count == 0)
{
return(false);
}
_current = _stack.Pop();
return(true);
}
}
protected override void InitPosition()
{
_current = _root;
while (SentinelEx.NotEqualNull(_current.LeftChild))
{
_stack.Push(_current);
_current = _current.LeftChild as TNode;
}
}
internal RecursiveEnumerator(TNode root)
{
if (SentinelEx.NotEqualNull(root))
{
_root = root;
_version = root.Version;
_stack = new Stack <TNode>();
}
else
{
_null = true;
}
}
public static bool IsAncestorOf(this BinaryTreeNode node, BinaryTreeNode target)
{
Contract.Requires <ArgumentNullException>(node != null);
Contract.Requires <ArgumentNullException>(target != null);
var p = target.Parent;
while (SentinelEx.NotEqualNull(p))
{
if (p == node)
{
return(true);
}
p = p.Parent;
}
return(false);
}
protected override bool MoveNextInternal()
{
if (SentinelEx.NotEqualNull(_current.RightChild))
{
_stack.Push(_current.RightChild as TNode);
}
if (SentinelEx.NotEqualNull(_current.LeftChild))
{
_current = _current.LeftChild as TNode;
return(true);
}
if (_stack.Count == 0)
{
return(false);
}
_current = _stack.Pop();
return(true);
}
public bool MoveNext()
{
if (_null)
{
return(false);
}
if (_version != _root.Version)
{
throw new InvalidOperationException("在枚举过程中树被修改过");
}
if (SentinelEx.EqualNull(_current))
{
if (SentinelEx.EqualNull(_root))
{
return(false);
}
InitPosition();
return(true);
}
return(MoveNextInternal());
}
public bool MoveNext()
{
if (_version != _root.Version)
{
throw new InvalidOperationException("在枚举过程中树被修改过");
}
if (_queue.Count == 0)
{
return(false);
}
_current = _queue.Dequeue();
if (SentinelEx.NotEqualNull(_current.LeftChild))
{
_queue.Enqueue(_current.LeftChild as TNode);
}
if (SentinelEx.NotEqualNull(_current.RightChild))
{
_queue.Enqueue(_current.RightChild as TNode);
}
return(true);
}
protected override bool MoveNextInternal()
{
if (_stack.Count == 0)
{
return(false);
}
if (_stack.Peek().LeftChild != _current && _stack.Peek().RightChild != _current)
{
TNode temp = _stack.Peek();
while (SentinelEx.NotEqualNull(temp))
{
if (SentinelEx.NotEqualNull(temp.LeftChild))
{
if (SentinelEx.NotEqualNull(temp.RightChild))
{
_stack.Push(temp.RightChild as TNode);
}
_stack.Push(temp.LeftChild as TNode);
}
else
{
if (SentinelEx.NotEqualNull(temp.RightChild))
{
_stack.Push(temp.RightChild as TNode);
}
else
{
break;
}
}
temp = _stack.Peek();
}
}
_current = _stack.Pop();
return(true);
}
public static int GetDegree(this IMultiwayTreeNode node)
{
Contract.Requires <ArgumentNullException>(node == null);
Contract.Ensures(Contract.Result <int>() >= 0);
return(node.Children?.Count(cnode => SentinelEx.NotEqualNull(cnode)) ?? 0);
}
public static TreeKind JudgeKind <TNode>(this IRootedTree <TNode> tree)
where TNode : class, IBinaryTreeNode
{
Contract.Requires <ArgumentNullException>(tree != null);
Contract.Requires <InvalidOperationException>(tree.Root != null, "树不能为空");
var last = tree.Root;
TreeKind result = TreeKind.Ordinary;
int degreelog = tree.Root.GetDegree();
int nstrict = 0;
int depthlog = -1;
bool newline = false, completeflag = true;
Func <int, IBinaryTreeNode, int> updatefunc = (int level, IBinaryTreeNode node) => level + 1;
foreach (var current in LevelOrderTraverse(tree.Root, 0, updatefunc, updatefunc))
{
var node = current.Item1;
var depth = current.Item2;
if (node.GetDegree() != 0)
{
if (node.GetDegree() != degreelog)
{
nstrict++;
if (nstrict > 1)
{
break; //more than one inner node differs with root, then it must be a ordinary tree.
}
}
}
else
{
if (depthlog == -1)
{
depthlog = depth;
}
else if (depth > depthlog)
{
if (newline)
{
completeflag = false;
}
else
{
newline = true;
}
}
}
last = node as TNode;
}
if (last != tree.Root && SentinelEx.EqualNull(last.Parent.LeftChild))
{
completeflag = false;
}
if (nstrict == 0)
{
if (degreelog == 2)
{
result |= TreeKind.Full;
}
else
{
result |= TreeKind.Strict;
}
}
if (nstrict <= 1 && completeflag)
{
if (!newline && (last == tree.Root || !SentinelEx.EqualNull(last.Parent.RightChild)))
{
result |= TreeKind.Perfect;
}
else
{
result |= TreeKind.Complete;
}
}
return(result);
}
