feat: add hashbrown

src/bin/03.rs

@@ -1,4 +1,4 @@
-use std::collections::HashSet;
+use hashbrown::HashSet;
 
 use itertools::Itertools;
 

src/bin/06.rs

@@ -1,4 +1,4 @@
-use std::collections::HashMap;
+use hashbrown::HashMap;
 
 use lazy_static::lazy_static;
 use regex::Regex;