Solve day 2 in Rust

rust/main.rs

@@ -2,10 +2,11 @@ mod puzzle;
 mod puzzles;
 use crate::puzzle::Puzzle;
 use puzzles::day1;
+use puzzles::day2;
 use std::fmt::Display;
 use std::fs;
 
-const PUZZLES: [&dyn SomePuzzle; 1] = [&day1::PUZZLE];
+const PUZZLES: [&dyn SomePuzzle; 2] = [&day1::PUZZLE, &day2::PUZZLE];
 
 fn main() {
     [false, true].iter().for_each(|is_real_data| {

rust/puzzles/day2.rs

@@ -0,0 +1,64 @@
+use crate::puzzle::Puzzle;
+
+pub const PUZZLE: Puzzle<Vec<(usize, usize)>, usize, 2> = Puzzle {
+    number: 2,
+    parser: |input| {
+        input
+            .strip_suffix("\n")
+            .unwrap()
+            .split(',')
+            .map(|range| {
+                match range
+                    .split('-')
+                    .map(|n| n.parse().unwrap())
+                    .collect::<Vec<usize>>()[..]
+                {
+                    [a, b] => (a, b),
+                    _ => panic!(),
+                }
+            })
+            .collect()
+    },
+    parts: [
+        |input| {
+            input
+                .into_iter()
+                .flat_map(|(l, u)| {
+                    (*l..(u + 1)).flat_map(|n| if is_repetition_2(n) { Some(n) } else { None })
+                })
+                .sum()
+        },
+        |input| {
+            input
+                .into_iter()
+                .flat_map(|(l, u)| {
+                    (*l..(u + 1)).flat_map(|n| if is_repetition_n(n) { Some(n) } else { None })
+                })
+                .sum()
+        },
+    ],
+};
+
+fn is_repetition_2(n: usize) -> bool {
+    let n = n.to_string();
+    let l = n.len();
+    let d = l / 2;
+    let r = l % 2;
+    if r == 0 { equal_chunks(&n, d) } else { false }
+}
+
+fn is_repetition_n(n: usize) -> bool {
+    let n = n.to_string();
+    let l = n.len();
+    let d = l / 2;
+    (1..(d + 1)).any(|i| equal_chunks(&n, i))
+}
+
+fn equal_chunks(n: &String, i: usize) -> bool {
+    let chars = n.chars().collect::<Vec<char>>();
+    let mut chunks = (chars[..]).chunks(i);
+    match chunks.next() {
+        None => true,
+        Some(x) => chunks.all(|y| y == x),
+    }
+}

rust/puzzles/mod.rs

@@ -1 +1,2 @@
 pub(crate) mod day1;
+pub(crate) mod day2;