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);
}
}
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 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);
}
