Add leading 0s to the single digit day crates

2022/day01/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day1"
+version = "0.1.0"

2022/day01/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "day1"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

2022/day01/src/main.rs

@@ -0,0 +1,44 @@
+use std::env;
+use std::fs;
+use std::str::Lines;
+
+fn get_calorie_totals(lines: Lines) -> Vec<u32> {
+    let mut elves: Vec<u32> = Vec::new();
+    let mut current_calorie_count: u32 = 0;
+
+    for line in lines {
+        if line.is_empty() {
+            elves.push(current_calorie_count);
+            current_calorie_count = 0;
+            continue;
+        }
+
+        let u32_value = u32::from_str_radix(&line, 10)
+            .expect(format!("Couldn't read u32 value from string: {}", line).as_str());
+        current_calorie_count += u32_value;
+    }
+
+    elves.sort_unstable_by(|a, b| b.cmp(a));
+    elves
+}
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+
+    let filename = args.get(1).expect("Missing filename argument");
+
+    let file_contents = fs::read_to_string(&filename).expect("Unable to read file");
+    let lines = file_contents.lines();
+    let elves = get_calorie_totals(lines);
+
+    println!(
+        "Part 1: Elf with highest calorie count in knapsack: {}",
+        elves[0]
+    );
+
+    let sum_of_top_three = &elves[0] + &elves[1] + &elves[2];
+    println!(
+        "Part 2: Elves with top 3 highest calorie counts in their knapsacks: {}, {}, {} = {}",
+        &elves[0], &elves[1], &elves[2], sum_of_top_three
+    );
+}