57 lines
1.1 KiB
Rust
57 lines
1.1 KiB
Rust
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use std::io::{self, Read};
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type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
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fn get_input_string() -> io::Result<String> {
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let mut buffer = String::new();
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io::stdin().read_to_string(&mut buffer)?;
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Ok(buffer)
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}
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fn main() -> Result<()> {
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let mass_list: Vec<_> = get_input_string()?
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.split("\n")
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.filter(|n| !n.is_empty())
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.map(|n| n.parse::<u64>().unwrap())
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.collect();
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part1(&mass_list);
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part2(&mass_list);
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Ok(())
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}
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fn part1(mass_list: &Vec<u64>) {
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let total: u64 = mass_list.iter()
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.copied()
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.map(fuel_req)
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.sum();
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println!("Part 1: {}", total);
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}
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fn fuel_req(mass: u64) -> u64 {
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let frac = mass / 3;
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if frac <= 2 {
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0
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} else {
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frac - 2
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}
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}
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fn part2(mass_list: &Vec<u64>) {
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let total: u64 = mass_list.iter()
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.copied()
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.map(full_fuel_req)
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.sum();
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println!("Part 2: {}", total);
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}
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fn full_fuel_req(mass: u64) -> u64 {
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let req = fuel_req(mass);
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if req == 0 {
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0
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} else {
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req + full_fuel_req(req)
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}
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}
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