fix: optimize day01

c/day01.c

@@ -56,18 +56,14 @@ int main() {
   qsort(left_column, len, sizeof(int), compare_ints);
   qsort(right_column, len, sizeof(int), compare_ints);
 
-  unsigned int *distances = malloc(len * sizeof(unsigned int));
   unsigned int sum = 0;
 
   for (size_t i = 0; i < len; i++) {
-    distances[i] = abs(left_column[i] - right_column[i]);
-    sum += distances[i];
+    sum += abs(left_column[i] - right_column[i]);
   }
   printf("Part One solution: sum is %u\n", sum);
-  free(distances);
 
   // --- Part Two ---
-  unsigned int *appear = malloc(len * sizeof(unsigned int));
   sum = 0;
 
   for (size_t i = 0; i < len; i++) {
@@ -77,12 +73,10 @@ int main() {
         count++;
       }
     }
-    appear[i] = left_column[i] * count;
-    sum += appear[i];
+    sum += left_column[i] * count;
   }
 
   printf("Part Two solution: sum is %u\n", sum);
-  free(appear);
   free(left_column);
   free(right_column);
 

cpp/day01.cc

@@ -33,7 +33,7 @@ read_file(const std::string &input) {
 int main() {
   // --- Part One ---
   auto [left_column, right_column] = read_file("crates/day01/input.txt");
-  std::vector<unsigned int> distances;
+  unsigned int sum = 0;
 
   if (left_column.size() != right_column.size()) {
     throw std::runtime_error("Column sizes do not match");
@@ -43,22 +43,20 @@ int main() {
   std::sort(right_column.begin(), right_column.end());
 
   for (size_t i = 0; i < left_column.size(); ++i) {
-    distances.push_back(
-        static_cast<unsigned int>(std::abs(left_column[i] - right_column[i])));
+    sum +=
+        (static_cast<unsigned int>(std::abs(left_column[i] - right_column[i])));
   }
 
-  unsigned int sum = std::accumulate(distances.begin(), distances.end(), 0u);
   std::cout << "Part One solution: sum is " << sum << std::endl;
 
   // --- Part Two ---
+  sum = 0;
   std::vector<unsigned int> appear;
   for (const auto &e : left_column) {
     unsigned int count =
         std::count(right_column.begin(), right_column.end(), e);
-    appear.push_back(static_cast<unsigned int>(e) * count);
+    sum += static_cast<unsigned int>(e) * count;
   }
-
-  sum = std::accumulate(appear.begin(), appear.end(), 0);
   std::cout << "Part Two solution: sum is " << sum << std::endl;
 
   return 0;

crates/day01/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "day01"
-version = "0.1.0"
+version = "0.1.1"
 edition = "2021"
 
 [lints]

crates/day01/src/main.rs

@@ -4,7 +4,6 @@ use std::io::{self, BufRead};
 fn main() {
     // --- Part One ---
     let (mut left_column, mut right_column) = read_file("crates/day01/input.txt").unwrap();
-    let mut distances: Vec<u32> = Vec::new();
 
     assert!(left_column.len() == right_column.len());
     #[cfg(feature = "unstable")]
@@ -20,24 +19,23 @@ fn main() {
         right_column.sort();
     }
 
+    let mut sum: i32 = 0;
     for (i, _) in left_column.iter().enumerate() {
-        distances.push((left_column[i] - right_column[i]).unsigned_abs());
+        sum += (left_column[i] - right_column[i]).abs();
     }
-    let mut sum: u32 = distances.iter().copied().sum();
     println!("Part One solution: sum is {sum}");
 
     // --- Part Two ---
-    let mut appear: Vec<u32> = Vec::new();
+    sum = 0;
     for e in &left_column {
         let count: i32 = right_column
             .iter()
             .filter(|&n| *n == *e)
             .count()
             .try_into()
             .unwrap();
-        appear.push((*e * count).try_into().unwrap());
+        sum += *e * count;
     }
-    sum = appear.iter().copied().sum();
     println!("Part Two solution: sum is {sum}");
 }