public IEnumerable <bool> problem24()
{
LockedBT root = new LockedBT(12, null);
root.Left = new LockedBT(10, root);
root.Left.Left = new LockedBT(4, root.Left);
root.Left.Right = new LockedBT(11, root.Left);
root.Right = new LockedBT(15, root);
root.Right.Left = new LockedBT(13, root.Right);
yield return(root.isLocked());
root.Left.Left.@lock();
yield return(root.isLocked());
}
private bool canLockOrUnlock()
{
if (this.numOfLockedDescendant > 0)
{
return(false);
}
for (LockedBT curr = this.Parent; curr != null; curr = curr.Parent)
{
if (curr.isLocked())
{
return(false);
}
}
;
return(true);
}
public bool unlock()
{
if (!this.isLocked())
{
return(false);
}
if (!this.canLockOrUnlock())
{
return(false);
}
for (LockedBT curr = this.Parent; curr != null; curr = curr.Parent)
{
curr.numOfLockedDescendant -= 1;
}
this.locked = false;
return(true);
}
public LockedBT(int data, LockedBT parent)
{
this.Parent = parent;
this.Data = data;
}
