binary_tree/bstree/bstree.rs
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/// ## Generic Search Binary Tree implementation
pub struct BinaryTree<T>
where
T: Clone + Ord + Eq + std::fmt::Debug,
{
/// Pointer holding the data can be None
pub elem: Option<Box<T>>,
/// Pointer to the right leaf
pub right: Option<Box<BinaryTree<T>>>,
/// Pointer to the left leaf
pub left: Option<Box<BinaryTree<T>>>,
}
//pub type BinaryTreeNode<T> = BinaryTree<T>;
impl<T> BinaryTree<T>
where
T: std::fmt::Debug + Clone + Ord,
{
/// Creates a new `BinaryTree<T>`
/// # Example
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// ```
pub fn new(elem: T) -> Self {
Self {
elem: Some(Box::new(elem)),
right: None,
left: None,
}
}
/// Deletes and returns the given element from the tree in O(log n)
/// If the element is not in the tree returns None
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// let x = a.delete(1);
/// assert_eq!(Some(x), a);
/// ```
pub fn delete(&mut self, del_elem: T) -> Option<T> {
if let Some(ref mut elem) = self.elem {
if del_elem < **elem {
if let Some(left) = &mut self.left {
left.delete(del_elem)
} else {
None
}
} else if del_elem > **elem {
if let Some(right) = &mut self.right {
right.delete(del_elem)
} else {
None
}
} else {
// Element found, now delete it
match (self.left.take(), self.right.take()) {
(None, right) => {
*self = BinaryTree {
elem: None,
left: None,
right,
};
Some(del_elem)
}
(left, None) => {
*self = BinaryTree {
elem: None,
left,
right: None,
};
Some(del_elem)
}
(Some(left), Some(right)) => {
let min_right = right.min().cloned();
*self = BinaryTree {
elem: min_right.map(Box::new),
left: Some(left),
right: Some(right),
};
Some(del_elem)
}
}
}
} else {
None
}
}
/// Inserts the given element into the tree
/// Time complexity -> O(log n)
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// a.insert(1);
/// ```
pub fn insert(&mut self, new_elem: T) {
match &mut self.elem {
Some(ref mut elem) => {
if new_elem < **elem {
if let Some(left) = &mut self.left {
left.insert(new_elem)
} else {
self.left = Some(Box::new(BinaryTree::new(new_elem)));
}
} else if new_elem > **elem {
if let Some(right) = &mut self.right {
right.insert(new_elem)
} else {
self.right = Some(Box::new(BinaryTree::new(new_elem)));
}
}
}
None => {
self.elem = Some(Box::new(new_elem));
}
}
}
/// Returns true if the list is empty
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// let b = a.is_empty();
/// assert_eq!(b, false);
/// ```
pub fn is_empty(&self) -> bool {
self.elem.is_none() && self.right.is_none() && self.left.is_none()
}
/// Returns true if the elemen is in the tree with O(log n) complexity
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// let b = a.contains(1);
/// assert_eq!(b, true);
/// ```
pub fn contains(&self, search_elem: T) -> bool {
match &self.elem {
Some(ref elem) => {
if search_elem == **elem {
true
} else if search_elem < **elem {
match &self.left {
Some(left) => left.contains(search_elem),
None => false,
}
} else {
match &self.right {
Some(right) => right.contains(search_elem),
None => false,
}
}
}
None => false,
}
}
/// Clears/Deallocates the tree entirely
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// a.insert(2);
/// a.clear();
/// assert_eq!(a.is_empty(), true);
/// ```
pub fn clear(&mut self) {
self.elem = None;
self.left = None;
self.right = None;
}
/// Returns the maximum value of the tree in O(log n)
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// a.insert(2);
/// let x = a.max().unwrap();
/// assert_eq!(x, 2);
/// ```
pub fn max(&self) -> Option<&T> {
match &self.right {
Some(right) => right.max(),
None => self.elem.as_ref().map(|boxed_elem| &**boxed_elem),
}
}
/// Returns the minimum value of the tree in O(log n)
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// a.insert(2);
/// let x = a.min().unwrap();
/// assert_eq!(x, 1);
/// ```
pub fn min(&self) -> Option<&T> {
match &self.left {
Some(left) => left.min(),
None => self.elem.as_ref().map(|boxed_elem| &**boxed_elem),
}
}
/// Returns the height value of the tree in O(log n)
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// a.insert(2);
/// let x = a.height().unwrap();
/// assert_eq!(x, 1);
/// ```
pub fn height(&self) -> usize {
match (&self.left, &self.right) {
(Some(left), Some(right)) => 1 + usize::max(left.height(), right.height()),
(Some(left), None) => 1 + left.height(),
(None, Some(right)) => 1 + right.height(),
(None, None) => 1,
}
}
/// Returns the total number of elements in the tree in O(n)
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// a.insert(2);
/// let x = a.count().unwrap();
/// assert_eq!(x, 2);
/// ```
pub fn count(&self) -> usize {
let left_count = self.left.as_ref().map_or(0, |left| left.count());
let right_count = self.right.as_ref().map_or(0, |right| right.count());
let current_count = if self.elem.is_some() { 1 } else { 0 };
left_count + right_count + current_count
}
/// Prints to screen the elements in inorder
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// a.insert(2);
/// a.inorder();
/// ```
pub fn inorder(&self) {
if let Some(left) = &self.left {
left.inorder();
}
if let Some(elem) = &self.elem {
println!("{:?}", elem);
}
if let Some(right) = &self.right {
right.inorder();
}
}
/// Prints to screen the elements in preorder
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// a.insert(2);
/// a.peorder();
/// ```
pub fn preorder(&self) {
if let Some(elem) = &self.elem {
println!("{:?}", elem);
}
if let Some(left) = &self.left {
left.preorder();
}
if let Some(right) = &self.right {
right.preorder();
}
}
/// Prints to screen the elements in postorder
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// a.insert(2);
/// a.postorder();
/// ```
pub fn postorder(&self) {
if let Some(left) = &self.left {
left.postorder();
}
if let Some(right) = &self.right {
right.postorder();
}
if let Some(elem) = &self.elem {
println!("{:?}", elem);
}
}
/// Inserts all the elements in the vector in the tree
/// Basic usage:
/// ```
/// let mut a = BinaryTree::new(1);
/// a.vec_insert([1,2,3]);
/// ```
pub fn vec_insert(&mut self, elems: Vec<T>) {
for i in elems {
self.insert(i);
}
}
}