let mut tree = DynTree::new(0.to_string());

let mut dfs = Traversal.dfs().over_nodes();

for _ in 0..total_depth {

let root = tree.root();

let leaves: Vec<_> = root.leaves_with(&mut dfs).map(|x| x.idx()).collect();

for idx in leaves {

let count = tree.len();

let mut node = tree.node_mut(idx);

for j in 0..num_children {

node.push_child((count + j).to_string());

}

}

}

tree

let input = build_tree(10, 4);

let expected_num_characters = 5234569;

// computation using iterators

let total_num_characters: usize = input

.iter()

.filter(|x| !x.starts_with('1'))

.map(|x| x.len())

.sum();

assert_eq!(total_num_characters, expected_num_characters);

#[cfg(feature = "parallel")]

{

// computation using parallel iterator: replace `iter()` with `par()`

let total_num_characters: usize = input

.par()

.filter(|x| !x.starts_with('1'))

.map(|x| x.len())

.sum();

assert_eq!(total_num_characters, expected_num_characters);

// configure parallel computation

let total_num_characters: usize = input

.par()

.filter(|x| !x.starts_with('1'))

.num_threads(2)

.chunk_size(64)

.map(|x| x.len())

.sum();

assert_eq!(total_num_characters, expected_num_characters);

// consuming parallel iterator: replace `into_iter` with `into_par`

let total_num_characters: usize = input

.into_par()

.filter(|x| !x.starts_with('1'))

.map(|x| x.len())

.sum();

assert_eq!(total_num_characters, expected_num_characters);

}