day 14 + 15 fix

Tom-the-Bomb · Dec 16, 2023 · 053788f · 053788f
1 parent b150983
commit 053788f
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Showing 2 changed files with 25 additions and 27 deletions.
diff --git a/src/bin/day14.rs b/src/bin/day14.rs
@@ -1,7 +1,7 @@
 //! Day 14: Parabolic Reflector Dish
 //!
 //! <https://adventofcode.com/2023/day/14>
-use std::{collections::HashMap, fmt::Display};
+use std::{collections::VecDeque, fmt::Display};
 use aoc_2023::Solution;
 
 pub struct Day14;
@@ -104,36 +104,34 @@ impl Day14 {
         )
     }
 
+    /// # Panics
+    ///
+    /// If the cycles vec is empty
     pub fn part_two<T: Display>(&self, inp: T) -> usize {
         let grid = Self::get_grid(inp);
 
-        let mut start = 0;
-        let mut next_term = Self::cycle(&grid);
-        let mut cycles = HashMap::from([(grid, 0)]);
-        for i in 1.. {
-            next_term = Self::cycle(&next_term);
+        let mut cycles = VecDeque::from([grid]);
+        let start = loop {
+            let next_term = Self::cycle(cycles
+                .back()
+                .unwrap()
+            );
 
-            if let Some(&index) =
-                cycles.get(&next_term)
+            if let Some(index) = cycles
+                .iter()
+                .position(|term| term == &next_term)
             {
-                start = index;
-                break;
+                break index;
             }
-            cycles.insert(next_term.clone(), i);
-        }
+            cycles.push_back(next_term);
+        };
 
         Self::get_load(
-            &cycles
-                .iter()
-                .find_map(|(grid, &index)|
-                    (index + 1
-                        == (1_000_000_000 - start)
-                        % (cycles.len() - start)
-                        + start
-                    )
-                    .then_some(grid)
-                )
-                .unwrap()
+            &cycles[
+                (1_000_000_000 - start)
+                % (cycles.len() - start)
+                + start
+            ]
         )
     }
 }

diff --git a/src/bin/day15.rs b/src/bin/day15.rs
@@ -9,7 +9,7 @@ pub struct Day15;
 impl Day15 {
     /// Hashing algorithm
     /// turns any string into an 8-bit integer
-    /// 
+    ///
     /// `((current_value + ascii_value(character)) * 17) % 256`
     fn hash<T>(string: T) -> u8
     where
@@ -34,7 +34,7 @@ impl Day15 {
     }
 
     /// # Panics
-    /// 
+    ///
     /// If neither a '=' or '-' exist in an entry in the input
     pub fn part_two<T: Display>(&self, inp: T) -> u32 {
         let inp = inp.to_string();
@@ -45,7 +45,7 @@ impl Day15 {
         {
             let (label, focus) = string
                 .split_once('=')
-                .unwrap_or_else(|| 
+                .unwrap_or_else(||
                     string
                         .split_once('-')
                         .unwrap()
@@ -80,7 +80,7 @@ impl Day15 {
                     // therefore this will never happen, so we do nothing
                     _ => (),
                 }
-            }   
+            }
         }
 
         boxes