fixes a bug in doing schlinkert prune on reversed list

src/display_information/uniquely_decodable.rs

@@ -6,13 +6,11 @@
 /// very closely.
 use std::collections::HashSet;
 
-/// Return true if the list is uniquely decodable, false if not
+/// Return true if the list is uniquely decodable, false if not. I
+/// don't _think_ we need to check reversed words in this case.
 pub fn check_decodability(c: &[String]) -> bool {
-    let is_c_uniquely_decodable_forwards = sardinas_patterson_theorem(vec_to_hash(c));
-    // We need to check both forward and reverse
-    let c_reversed = reverse_all_words(c);
-    let is_c_uniquely_decodable_backwards = sardinas_patterson_theorem(vec_to_hash(&c_reversed));
-    is_c_uniquely_decodable_forwards || is_c_uniquely_decodable_backwards
+    let is_c_uniquely_decodable = sardinas_patterson_theorem(vec_to_hash(c));
+    is_c_uniquely_decodable
 }
 
 fn vec_to_hash(v: &[String]) -> HashSet<String> {
@@ -77,14 +75,6 @@ fn generate_c_infinity_with_a_halt_break(c: HashSet<String>) -> HashSet<String>
     c_infinity
 }
 
-fn reverse_all_words(list: &[String]) -> Vec<String> {
-    let mut reversed_list = vec![];
-    for word in list {
-        reversed_list.push(word.chars().rev().collect::<String>());
-    }
-    reversed_list
-}
-
 /// Returns true if c is uniquely decodable
 fn sardinas_patterson_theorem(c: HashSet<String>) -> bool {
     let c_infinity = generate_c_infinity_with_a_halt_break(c.clone());

src/list_manipulations.rs

@@ -146,9 +146,11 @@ pub fn guarantee_maximum_prefix_length(
 pub fn schlinkert_prune(list: &[String]) -> Vec<String> {
     let offenders_to_remove_forwards = get_sardinas_patterson_final_intersection(list);
     // Reversing all words before running the Schlinkert prune gives a
-    // different list of offending words
-    let offenders_to_remove_backwards =
-        get_sardinas_patterson_final_intersection(&reverse_all_words(list));
+    // different list of offending words. (We then have to un-reverse all the
+    // offending words.)
+    let offenders_to_remove_backwards = reverse_all_words(
+        &get_sardinas_patterson_final_intersection(&reverse_all_words(list)),
+    );
     let mut new_list = list.to_owned();
     // If running the prune on the reversed words yielded fewer offenders
     // we'll use that list, since our assumed goal is to remove the fewest