day 6

src/days/day6.rs

@@ -0,0 +1,43 @@
+use aoc_runner_derive::aoc;
+use itertools::Itertools;
+
+#[aoc(day6, part1, tuple_windows)]
+fn part1_tuple_windows(input: &str) -> usize {
+    input
+        .char_indices()
+        .tuple_windows()
+        .find_map(|((_, a), (_, b), (_, c), (i, d))| {
+            if [a, b, c, d].iter().duplicates().count() == 0 {
+                Some(i + d.len_utf8())
+            } else {
+                None
+            }
+        })
+        .unwrap()
+}
+
+#[aoc(day6, part1, indexing)]
+fn part1_indexing(input: &str) -> usize {
+    const N: usize = 4;
+
+    for i in N..=input.len() {
+        let s = &input[i - N..i];
+        if s.chars().duplicates().count() == 0 {
+            return i;
+        }
+    }
+    usize::MAX
+}
+
+#[aoc(day6, part2)]
+fn part2(input: &str) -> usize {
+    const N: usize = 14;
+
+    for i in N..=input.len() {
+        let s = &input[i - N..i];
+        if s.chars().duplicates().count() == 0 {
+            return i;
+        }
+    }
+    usize::MAX
+}

src/lib.rs

@@ -6,6 +6,7 @@ mod days {
     mod day3;
     mod day4;
     mod day5;
+    mod day6;
 }
 
 aoc_lib! { year = 2022 }