Map on the data within the node instead of the node itself
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@ -60,14 +60,23 @@ impl<T> Tree<T> {
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None
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}
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/// Convert each node of a tree from type T to type U
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pub fn map<F, U>(&self, op: F) -> Tree<U>
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where
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F: FnOnce(&Node<T>) -> Node<U> + Copy,
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F: FnOnce(&T) -> U + Copy,
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{
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// A key part of this is to avoid recursion. There is no telling how deep a tree may go (Go
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// game records can go hundreds of nodes deep), so we're going to just avoid recursion.
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match self {
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Tree::Empty => Tree::Empty,
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Tree::Root(root) => {
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let new_root = op(root);
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let new_root = Node::new(op(&root.value()));
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// This queue serves as a work list. Each node in the queue needs to be converted,
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// and I've paired the node up with the one that it's supposed to be attached to.
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// So, as we look at a node A, we make sure that all of its children gets added to
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// the queue, and that the queue knows that the conversion of each child node
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// should get attached to A.
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let mut queue: VecDeque<(Node<T>, Node<U>)> = root
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.children()
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.iter()
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@ -75,7 +84,7 @@ impl<T> Tree<T> {
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.collect();
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while let Some((source, dest)) = queue.pop_front() {
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let res = op(&source);
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let res = Node::new(op(&source.value()));
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dest.add_child_node(res.clone());
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for child in source.children().iter() {
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@ -174,7 +183,7 @@ mod tests {
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let n = n.add_child_value(16);
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let _ = n.add_child_value(17);
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let tree2 = tree.map(|v| Node::new(v.value().to_string()));
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let tree2 = tree.map(|v| v.to_string());
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assert!(tree2.find_bfs(|val| *val == "15").is_some());
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assert!(tree2.find_bfs(|val| *val == "16").is_some());
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