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December 6, 2020 01:59
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Advent of Code - Day 5 - Rust
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use std::fs::File; | |
use std::io::prelude::*; | |
use std::collections::HashSet; | |
#[derive(Debug)] | |
struct BoardingPass { | |
row: u8, | |
col: u8, | |
id: u16, | |
} | |
fn parse_boarding_pass(line: &str) -> BoardingPass { | |
let (row_data, col_data) = line.split_at(7); | |
let (row, _) = row_data.chars().fold((0, 127), |acc, c| -> (u8, u8) { | |
match c { | |
'F' => (acc.0, (acc.0 + acc.1)/2), | |
'B' => ((acc.0 + acc.1)/2 + 1, acc.1), | |
_ => (0, 0), | |
} | |
}); | |
let (col, _) = col_data.chars().fold((0, 7), |acc, c| -> (u8, u8) { | |
match c { | |
'L' => (acc.0, (acc.0 + acc.1)/2), | |
'R' => ((acc.0 + acc.1)/2 + 1, acc.1), | |
_ => (0, 0), | |
} | |
}); | |
BoardingPass { | |
row, | |
col, | |
id: 8 * (row as u16) + col as u16, | |
} | |
} | |
fn initialize_array(arr: &mut Vec<BoardingPass>) { | |
let mut file = File::open("./input").unwrap(); | |
let mut contents = String::new(); | |
file.read_to_string(&mut contents).unwrap(); | |
for line in contents.split('\n') { | |
arr.push(parse_boarding_pass(line)); | |
} | |
} | |
fn problem1(boarding_passes: &Vec<BoardingPass>) { | |
let max = boarding_passes.iter().fold(0, |acc, b| -> u16 { | |
if b.id > acc { | |
return b.id | |
} else { | |
acc | |
} | |
}); | |
println!("Problem 1 -> {}", max); | |
} | |
fn problem2(boarding_passes: &Vec<BoardingPass>) { | |
let mut seats = HashSet::new(); | |
let max = boarding_passes.iter().fold(0, |acc, b| { | |
seats.insert(b.id); | |
if b.id > acc { | |
return b.id | |
} else { | |
acc | |
} | |
}); | |
let mut seat: u16 = 0; | |
for i in 1..(max - 2) { | |
if seats.contains(&(i - 1)) && seats.contains(&(i + 1)) && !seats.contains(&i) { | |
seat = i; | |
break; | |
} | |
} | |
println!("Problem 2 -> {}", seat); | |
} | |
fn main() { | |
let mut boarding_passes = Vec::<BoardingPass>::new(); | |
initialize_array(&mut boarding_passes); | |
problem1(&boarding_passes); | |
problem2(&boarding_passes); | |
} |
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