private Couple <int> GetTwoMaxValue(BinaryNode <int> root)
{
if (root.ChildrenCount() == 0)
{
return(new Couple <int>(root.Value, int.MinValue));
}
SortedList <int> sortedList = new SortedList <int>(false);
// Left child
Couple <int> left = GetTwoMaxValue(root.Left);
sortedList.Add(left.First);
sortedList.Add(left.Second);
// Right child
if (root.ChildrenCount() == 2)
{
Couple <int> right = GetTwoMaxValue(root.Right);
sortedList.Add(right.First);
sortedList.Add(right.Second);
}
// Root
sortedList.Add(root.Value);
// Extract two max values
List <int> list = sortedList.ToList();
return(new Couple <int>(list[0], list[1]));
}
private int CountUniversalSubtree(BinaryNode <int> root)
{
int count = 0;
if (1 == root.ChildrenCount())
{
count = CountUniversalSubtree(root.Left);
}
else if (2 == root.ChildrenCount())
{
count = CountUniversalSubtree(root.Left);
count += CountUniversalSubtree(root.Right);
}
if (IsUniversalTree(root))
{
count++;
}
return(count);
}
private bool IsUniversalTree(BinaryNode <int> root)
{
int childrenCount = root.ChildrenCount();
if (0 == childrenCount)
{
return(true);
}
if (1 == childrenCount)
{
return(IsUniversalTree(root.Left) && root.Value.Equals(root.Left.Value));
}
else
{
return(IsUniversalTree(root.Left) &&
IsUniversalTree(root.Right) &&
root.Value.Equals(root.Left.Value) &&
root.Value.Equals(root.Right.Value));
}
}