77 lines
1.7 KiB
Rust
77 lines
1.7 KiB
Rust
use std::fmt::Write;
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use anyhow::Result;
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const INPUT: &str = include_str!("../input/day01.txt");
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pub fn run() -> Result<String> {
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let mut res = String::with_capacity(128);
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writeln!(res, "part 1: {}", part1(INPUT)?)?;
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writeln!(res, "part 2: {}", part2(INPUT)?)?;
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Ok(res)
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}
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fn fuel_needed(module_weight: u64) -> u64 {
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(module_weight / 3).saturating_sub(2)
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}
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fn part1(input: &str) -> Result<u64> {
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input
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.lines()
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.map(str::parse)
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.map(|w| w.map(fuel_needed).map_err(anyhow::Error::new))
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.sum()
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}
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fn cumulated_fuel_needed(module_weight: u64) -> u64 {
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let mut total_fuel = fuel_needed(module_weight);
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let mut additional_fuel = fuel_needed(total_fuel);
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while additional_fuel != 0 {
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total_fuel += additional_fuel;
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additional_fuel = fuel_needed(additional_fuel);
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}
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total_fuel
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}
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fn part2(input: &str) -> Result<u64> {
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input
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.lines()
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.map(str::parse)
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.map(|w| w.map(cumulated_fuel_needed).map_err(anyhow::Error::new))
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.sum()
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn part1_provided() {
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assert_eq!(fuel_needed(12), 2);
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assert_eq!(fuel_needed(14), 2);
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assert_eq!(fuel_needed(1969), 654);
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assert_eq!(fuel_needed(100756), 33583);
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}
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#[test]
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fn part1_real() {
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assert_eq!(part1(INPUT).unwrap(), 3268951);
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}
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#[test]
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fn part2_provided() {
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assert_eq!(cumulated_fuel_needed(14), 2);
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assert_eq!(cumulated_fuel_needed(1969), 966);
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assert_eq!(cumulated_fuel_needed(100756), 50346);
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}
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#[test]
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fn part2_real() {
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assert_eq!(part2(INPUT).unwrap(), 4900568);
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}
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}
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