advent-of-code/2022/rust/day01.rs

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Rust
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2022-12-09 16:43:00 +00:00
use std::{
fs::File,
io::{prelude::*, BufReader},
path::Path,
};
fn lines_from_file(filename: impl AsRef<Path>) -> Vec<String> {
let file = File::open(filename).expect("no such file");
let buf = BufReader::new(file);
buf.lines()
.map(|l| l.expect("Could not parse line"))
.collect()
}
// ---
fn main() {
let lines = lines_from_file("../full/day01.txt");
part1(&lines);
part2(&lines);
}
fn part1(lines: &Vec<String>) {
let mut totals: Vec<i32> = Vec::new();
let mut total = 0;
for line in lines {
if line.is_empty(){
totals.push(total);
total = 0;
} else {
total += line.parse::<i32>().unwrap();
}
}
totals.sort_by(|a, b| a.partial_cmp(b).unwrap());
println!("{:?}", totals[totals.len()-1]);
}
fn part2(lines: &Vec<String>) {
let mut totals: Vec<i32> = Vec::new();
let mut total = 0;
for line in lines {
if line.is_empty(){
totals.push(total);
total = 0;
} else {
total += line.parse::<i32>().unwrap();
}
}
totals.sort_by(|a, b| a.partial_cmp(b).unwrap());
let last3 = &totals[totals.len()-3..];
let total: i32 = last3.iter().sum();
println!("{:?}", total);
}