Day1 of AoC 2022 in Rust. That was... somewhat painful. And I haven't even needed to get to the borrow checker stuff yet

day1/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"

day1/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]

day1/src/main.rs

@@ -0,0 +1,25 @@
+use std::fs;
+
+fn main() {
+    let contents = fs::read_to_string("data.txt").expect("Failed to read file");
+    // break into groups divided by empty lines
+    let groups: Vec<&str> = contents.trim().split("\n\n").collect();
+    // turn into vectors of vectors of strings
+    let groups: Vec<Vec<&str>> = groups.iter().map(|&x| x.split("\n").collect()).collect();
+    // map parsing to u32
+    let nums: Vec<Vec<u32>> = groups.iter().map(|x| x.iter().map(|&y| y.parse().unwrap()).collect()).collect();
+    // sum each group
+    let mut sums: Vec<u32> = nums.iter().map(|x| x.iter().sum()).collect();
+    // find the max
+    let max = sums.iter().max().unwrap();
+
+    println!("Max Calories: {:?}", max);
+
+    sums.sort();
+    sums.reverse();
+
+    let (top3, _) = sums.split_at(3);
+    let top3_sum = top3.iter().sum::<u32>();
+
+    println!("Top 3 Max Calories: {:?}", top3_sum);
+}

day1/test.txt

@@ -0,0 +1,14 @@
+1000
+2000
+3000
+
+4000
+
+5000
+6000
+
+7000
+8000
+9000
+
+10000