Optimize & simplify day 1

bram/rust/inputs/02.txt

@@ -0,0 +1,2 @@
+8123221734-8123333968,2665-4538,189952-274622,4975-9031,24163352-24202932,1233-1772,9898889349-9899037441,2-15,2147801-2281579,296141-327417,8989846734-8989940664,31172-42921,593312-632035,862987-983007,613600462-613621897,81807088-81833878,13258610-13489867,643517-782886,986483-1022745,113493-167913,10677-16867,372-518,3489007333-3489264175,1858-2534,18547-26982,16-29,247-366,55547-103861,57-74,30-56,1670594-1765773,76-129,134085905-134182567,441436-566415,7539123416-7539252430,668-1146,581563513-581619699
+

bram/rust/src/day_01/mod.rs

@@ -1,55 +1,41 @@
 use crate::utils;
 
-struct Dial {
-    points_at : i16,
-    clicks : u32,
-    passing_clicks : u32,
-}
-impl Dial {
-    fn new() -> Dial {
-        Dial { points_at : 50, clicks : 0, passing_clicks : 0 }
-    }
-
-    fn rotate_by(&mut self, r : i16) -> () {
-        let start : i16 = self.points_at;
-
-        self.points_at += r;
-        self.points_at = self.points_at.rem_euclid(100);
-        self.passing_clicks += (r.abs() / 100) as u32;
-
-        if self.points_at == 0 {
-            self.clicks += 1;
-
-            // Avoid double counting when starting and landing on zero
-            if r / 100 != 0 && r % 100 == 0 {
-                self.passing_clicks -= 1;
-            }
-        }
-
-        if r < 0 && start < self.points_at && start != 0 {
-            self.passing_clicks += 1;
-        }
-        if r > 0 && start > self.points_at && self.points_at != 0 {
-            self.passing_clicks += 1;
-        }
-
-        // println!(
-        //     "Dial {} now points at {} ({} clicks, {} passing)",
-        //     r, self.points_at, self.clicks, self.passing_clicks
-        // );
-    }
-}
-
-pub fn answer(text : String) ->( u32, u32 ) {
-    let mut dial : Dial = Dial::new();
+pub fn answer(text : String) ->( u16, u16 ) {
+    let mut old : i16 = 50;
+    let mut clicks : u16 = 0;
+    let mut passing_clicks : u16 = 0;
 
     for d in text.split("\n").filter_map(str_to_dir) {
-        dial.rotate_by(d);
+        let new : i16 = old + d;
+
+        // Part 1 clicks
+        if new % 100 == 0 {
+            clicks += 1;
+        }
+
+        // Part 2 clicks
+        if d > 0 {
+            passing_clicks += (
+                new.div_euclid(100) - old.div_euclid(100)
+            ) as u16
+        } else {
+            passing_clicks += (
+                (old - 1).div_euclid(100) - (new - 1).div_euclid(100)
+            ) as u16
+        }
+
+        old = new;
     }
 
-    ( dial.clicks
-    , dial.clicks + dial.passing_clicks
-    )
+    ( clicks, passing_clicks )
+}
+
+fn count_passing_clicks(old : i16, new : i16) -> u16 {
+    if old < new {
+        (new.div_euclid(100) - old.div_euclid(100)).abs() as u16
+    } else {
+        ((new - 1).div_euclid(100) - (old - 1).div_euclid(100)).abs() as u16
+    }
 }
 
 fn str_to_dir(s : &str) -> Option<i16> {

bram/rust/src/day_02/mod.rs

@@ -0,0 +1,50 @@
+use crate::utils;
+use std::ops::RangeInclusive;
+
+pub fn answer(text : String) -> ( u64, u64 ) {
+    ( text.split(",").flat_map(to_range).filter(|x| is_invalid_by(x, 2)).sum()
+    , text.split(",").flat_map(to_range).filter(is_invalid).sum()
+    )
+}
+
+fn is_invalid(n : &u64) -> bool {
+    for b in 2..=10 {
+        if is_invalid_by(n, b) {
+            return true;
+        }
+    }
+
+    false
+}
+
+fn is_invalid_by(n : &u64, by : usize) -> bool {
+    let s : String = n.to_string();
+    let size : usize = s.len() / by;
+
+    if s.len() % by == 0 {
+        for i in 1..by {
+            if s[0..size] != s[i * size..(i + 1) * size] {
+                return false;
+            }
+        }
+
+        true
+    } else {
+        false
+    }
+}
+
+fn to_range(s : &str) -> RangeInclusive<u64> {
+    let empty = 1..=0;
+    if let Some((low, high)) = s.split_once("-") {
+        match ( utils::str_to_u64(low), utils::str_to_u64(high) ) {
+            ( Some(l), Some(h) ) =>
+                l..=h,
+            _ =>
+                // Empty iterator
+                empty,
+        }
+    } else {
+        empty
+    }
+}

bram/rust/src/lib.rs

@@ -1,5 +1,5 @@
 mod day_01;
-// mod day_02;
+mod day_02;
 // mod day_03;
 // mod day_04;
 // mod day_05;
@@ -26,12 +26,12 @@ pub fn day_01() -> DailyOutput {
     ( p1 as u128, p2 as u128, d )
 }
 
-// pub fn day_02() -> DailyOutput {
-//     let s : String = read_from_file("inputs/02.txt");
-//     let (p1, p2, d) = diagnostics::benchmark(s, day_02::answer);
+pub fn day_02() -> DailyOutput {
+    let s : String = read_from_file("inputs/02.txt");
+    let (p1, p2, d) = diagnostics::benchmark(s, day_02::answer);
 
-//     ( p1 as u128, p2 as u128, d )
-// }
+    ( p1 as u128, p2 as u128, d )
+}
 
 // pub fn day_03() -> DailyOutput {
 //     let s : String = read_from_file("inputs/03.txt");

bram/rust/src/main.rs

@@ -2,7 +2,7 @@ fn main() {
     let mut aoc = aoc2025::AdventOfCode::new();
 
     aoc.insert(1, aoc2025::day_01());
-    // aoc.insert(2, aoc2025::day_02());
+    aoc.insert(2, aoc2025::day_02());
     // aoc.insert(3, aoc2025::day_03());
     // aoc.insert(4, aoc2025::day_04());
     // aoc.insert(5, aoc2025::day_05());

bram/rust/src/utils/mod.rs

@@ -36,6 +36,6 @@ pub fn str_to_i16(s : &str) -> Option<i16> {
 //     s.trim().to_string().parse::<u32>().ok()
 // }
     
-// pub fn str_to_u64(s : &str) -> Option<u64> {
-//     s.trim().to_string().parse::<u64>().ok()
-// }
+pub fn str_to_u64(s : &str) -> Option<u64> {
+    s.trim().to_string().parse::<u64>().ok()
+}