attempt to do away with BTreeMap

src/uu/tsort/src/tsort.rs

@@ -3,7 +3,7 @@
 // For the full copyright and license information, please view the LICENSE
 // file that was distributed with this source code.
 use clap::{crate_version, Arg, Command};
-use std::collections::{BTreeMap, HashSet, VecDeque};
+use std::collections::{HashMap, HashSet, VecDeque};
 use std::fmt::Write;
 use std::fs::File;
 use std::io::{stdin, BufReader, Read};
@@ -132,14 +132,14 @@ impl<'input> Node<'input> {
 }
 
 struct Graph<'input> {
- nodes: BTreeMap<&'input str, Node<'input>>,
+ nodes: HashMap<&'input str, Node<'input>>,
  result: Result<Vec<&'input str>, Vec<&'input str>>,
 }
 
 impl<'input> Graph<'input> {
  fn new() -> Self {
  Self {
- nodes: BTreeMap::new(),
+ nodes: HashMap::new(),
  result: Ok(Vec::new()),
  }
  }
@@ -176,7 +176,7 @@ impl<'input> Graph<'input> {
  }
  })
  .collect();
-
+ independent_nodes_queue.make_contiguous().sort_unstable();
  while let Some(name_of_next_node_to_process) = independent_nodes_queue.pop_front() {
  result.push(name_of_next_node_to_process);
  if let Some(node_to_process) = self.nodes.remove(name_of_next_node_to_process) {