abuse a nighly feature instead of a dependency

src/day03.rs

@@ -1,5 +1,3 @@
-use itertools::Itertools;
-
 pub fn process_part_1(input: &str) -> u32 {
     input
         .lines()
@@ -23,16 +21,11 @@ pub fn process_part_1(input: &str) -> u32 {
 pub fn process_part_2(input: &str) -> u32 {
     let result = input
         .lines()
-        .chunks(3)
-        .into_iter()
-        .map(|chunk| {
-            let lines: Vec<_> = chunk
-                .map(|l| l.chars().unique().collect::<Vec<_>>())
-                .collect();
-
-            let overlap = *lines[0]
-                .iter()
-                .find(|c| lines[1].contains(*c) && lines[2].contains(*c))
+        .array_chunks::<3>()
+        .map(|[a, b, c]| {
+            let overlap = a
+                .chars()
+                .find(|chr| b.contains(*chr) && c.contains(*chr))
                 .unwrap();
 
             match overlap {

src/lib.rs

@@ -1,3 +1,4 @@
+#![feature(iter_array_chunks)]
 extern crate core;
 
 pub mod day01;