/// Returns a optional reference to maximum key
///
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// use treers::bst::BST;
/// use treers::SedgewickMap;
///
/// let mut bst: BST<char, i32> = BST::new();
/// assert_eq!(bst.max(), None);
/// bst.put('c', 1);
/// bst.put('a', 2);
/// bst.put('b', 3);
/// bst.put('d', 4);
/// assert_eq!(bst.max(), Some(&'d'));
/// ```
Returns a optional reference to maximum key
Returns a optional reference to maximum key
fn max(&self) -> Option<&K> {
        match self {
            BST::Node {
                ref k,
                v: _,
                size: _,
                left: _,
                ref right,
            } => {
                if let Some(l) = right.max() {
                    Some(l)
                } else {
                    Some(k)
                }
            }
            _ => None,
        }
    }
fn max ( & self ) -> Option < & K > { match self { BST :: Node { ref k , v : _ , size : _ , left : _ , ref right , } => { if let Some ( l ) = right . max ( ) { Some ( l ) } else { Some ( k ) } } _ => None , } }
Returns a optional reference to maximum key
Returns a optional reference to maximum key
&self
examples
Basic usage.

```
use treers::bst::BST;
use treers::SedgewickMap.


Basic usage . ` ` ` use treers :: bst :: BST ; use treers :: SedgewickMap .