refactor: Use a dynamic window!

icyJoseph · Dec 1, 2021 · e101c4b · e101c4b
1 parent f5e5bce
commit e101c4b
Show file tree

Hide file tree

Showing 2 changed files with 13 additions and 32 deletions.
diff --git a/2021/day-1/src/main.rs b/2021/day-1/src/main.rs
@@ -14,39 +14,27 @@ fn solve(raw: String) -> () {
         .map(|x| parse_num::<u32>(x))
         .collect::<Vec<u32>>();
 
-    let part_one_deltas = rows[1..]
-        .iter()
-        .scan(rows[0], |state, curr| {
-            let diff = curr > state;
+    let compare = |state: &mut usize, curr: &u32| {
+        let result = *curr > rows[*state];
+        *state += 1;
 
-            *state = *curr;
+        Some(result)
+    };
 
-            Some(diff)
-        })
+    let part_one_deltas = rows[1..]
+        .iter()
+        .scan(0usize, compare)
         .filter(|x| *x)
         .count();
 
     println!("Part one: {}", part_one_deltas); // 1226
 
-    let windows: Vec<u32> = rows[..rows.len() - 2]
+    let part_two_deltas = rows[3..]
         .iter()
-        .scan(0usize, |state, curr| {
-            let window_sum = curr + rows[*state + 1..*state + 3].iter().sum::<u32>();
-            *state += 1;
-
-            Some(window_sum)
-        })
-        .collect();
-
-    let part_two_deltas = windows[1..]
-        .iter()
-        .scan(0usize, |state, curr| {
-            let index = *state;
-            *state += 1;
-            Some(*curr > windows[index])
-        })
+        .scan(0usize, compare)
         .filter(|x| *x)
         .count();
+
     println!("Part two: {}", part_two_deltas); // 1252
 }
 

diff --git a/2021/deno/day-1.ts b/2021/deno/day-1.ts
@@ -23,16 +23,9 @@ console.log("Part One:", deltas);
 
 const windowDeltas = data
   .reduce((prev: boolean[], _, index, src) => {
-    if (index === 0) return prev;
-    if (src.length - index < 3) return prev;
-
-    const prevWindow = src.slice(index - 1, index + 2);
-    const nextWindow = src.slice(index, index + 3);
-
-    const prevSum = prevWindow.reduce(sum);
-    const nextSum = nextWindow.reduce(sum);
+    if (index < 3) return prev;
 
-    return [...prev, nextSum > prevSum];
+    return [...prev, src[index] > src[index - 3]];
   }, [])
   .filter(Boolean).length;