2022 day6/rust: cleanup

2022/day6/rust/src/main.rs

@@ -1,29 +1,25 @@
 #![warn(clippy::pedantic)]
 
-use std::{
-    collections::HashSet,
-    io::{stdin, Read},
-};
+use std::io::{stdin, Read};
 
-use aoc::*;
+fn all_distinct<T: Ord>(slice: &[T]) -> bool {
+    slice
+        .iter()
+        .enumerate()
+        .all(|(i, x)| slice[i + 1..].iter().all(|y| y != x))
+}
+
+fn end_of_first_distinct_run<T: Ord>(data: &[T], len: usize) -> Option<usize> {
+    data.windows(len)
+        .position(|cs| all_distinct(cs))
+        .map(|i| i + len)
+}
 
 fn main() {
     let mut data = String::new();
     stdin().read_to_string(&mut data).unwrap();
+    let data = data.as_bytes();
 
-    let i = data
-        .as_bytes()
-        .windows(4)
-        .position(|cs| HashSet::<u8>::from_iter(cs.into_iter().copied()).len() == 4)
-        .unwrap();
-
-    println!("{:?}", i + 4);
-
-    let i = data
-        .as_bytes()
-        .windows(14)
-        .position(|cs| HashSet::<u8>::from_iter(cs.into_iter().copied()).len() == 14)
-        .unwrap();
-
-    println!("{:?}", i + 14);
+    println!("{:?}", end_of_first_distinct_run(data, 4).unwrap());
+    println!("{:?}", end_of_first_distinct_run(data, 14).unwrap());
 }