Add a tree map operation

This commit is contained in:
Savanni D'Gerinel 2023-10-20 23:43:47 -04:00
parent c2e78d7c54
commit 0fbfb4f1ad
1 changed files with 55 additions and 5 deletions

View File

@ -9,7 +9,7 @@ use std::{
rc::Rc, rc::Rc,
}; };
#[derive(Debug)] #[derive(Clone, Debug)]
pub enum Tree<T> { pub enum Tree<T> {
Empty, Empty,
Root(Node<T>), Root(Node<T>),
@ -22,8 +22,16 @@ impl<T> Default for Tree<T> {
} }
impl<T> Tree<T> { impl<T> Tree<T> {
pub fn set_value(&mut self, value: T) { pub fn new(value: T) -> (Tree<T>, Node<T>) {
*self = Tree::Root(Node::new(value)); let node = Node::new(value);
let tree = Tree::Root(node.clone());
(tree, node)
}
pub fn set_value(&mut self, value: T) -> Node<T> {
let node = Node::new(value);
*self = Tree::Root(node.clone());
node
} }
/// Use a breadth-first-search pattern to find a node, returning the node if found. /// Use a breadth-first-search pattern to find a node, returning the node if found.
@ -51,6 +59,33 @@ impl<T> Tree<T> {
} }
None None
} }
pub fn map<F, U>(&self, op: F) -> Tree<U>
where
F: FnOnce(&Node<T>) -> Node<U> + Copy,
{
match self {
Tree::Empty => Tree::Empty,
Tree::Root(root) => {
let new_root = op(root);
let mut queue: VecDeque<(Node<T>, Node<U>)> = root
.children()
.iter()
.map(|child| (child.clone(), new_root.clone()))
.collect();
while let Some((source, dest)) = queue.pop_front() {
let res = op(&source);
dest.add_child_node(res.clone());
for child in source.children().iter() {
queue.push_back((child.clone(), res.clone()));
}
}
Tree::Root(new_root)
}
}
}
} }
// By using the Rc<RefCell> container here, I'm able to make Node easily clonable while still // By using the Rc<RefCell> container here, I'm able to make Node easily clonable while still
@ -100,8 +135,10 @@ impl<T> Node<T> {
self.0.borrow_mut().children.push(child) self.0.borrow_mut().children.push(child)
} }
pub fn add_child_value(&self, value: T) { pub fn add_child_value(&self, value: T) -> Node<T> {
self.0.borrow_mut().children.push(Node::new(value)) let node = Node::new(value);
self.0.borrow_mut().children.push(node.clone());
node
} }
} }
@ -130,4 +167,17 @@ mod tests {
assert_eq!(*n.value(), 15); assert_eq!(*n.value(), 15);
// assert_eq!(n.children(), vec![Rc::new(RefCell::new(Node::new(20)))]); // assert_eq!(n.children(), vec![Rc::new(RefCell::new(Node::new(20)))]);
} }
#[test]
fn it_can_map_one_tree_to_another() {
let (tree, n) = Tree::new(15);
let n = n.add_child_value(16);
let _ = n.add_child_value(17);
let tree2 = tree.map(|v| Node::new(v.value().to_string()));
assert!(tree2.find_bfs(|val| *val == "15").is_some());
assert!(tree2.find_bfs(|val| *val == "16").is_some());
assert!(tree2.find_bfs(|val| *val == "17").is_some());
}
} }