diff options
Diffstat (limited to 'aoc21/src')
-rw-r--r-- | aoc21/src/main.rs | 233 |
1 files changed, 0 insertions, 233 deletions
diff --git a/aoc21/src/main.rs b/aoc21/src/main.rs deleted file mode 100644 index 1366f1e..0000000 --- a/aoc21/src/main.rs +++ /dev/null @@ -1,233 +0,0 @@ -extern crate regex; - -use std::io::BufReader; -use std::io::prelude::*; -use std::fs::File; -use std::collections::VecDeque; - -use regex::Regex; - -fn main() { - let password = "abcdefgh".to_string(); - let program = read_file(); - let scrambled = scramble_password(password, &program); - println!("Scrambled password is {}", scrambled); - let unscrambled = unscramble_password(scrambled, &program); - println!("Which unscrambles to {}", unscrambled); - - let other_scrambled = "fbgdceah".to_string(); - let other_unscrambled = unscramble_password(other_scrambled, &program); - - println!("Decrypted easter bunny password is {}", other_unscrambled); -} - -fn read_file() -> Vec<String> { - let file = BufReader::new(File::open("input.txt").unwrap()); - file.lines() - .map(|line| line.unwrap().trim().to_string()) - .filter(|line| line.len() > 0) - .collect() -} - -fn scramble_password(password: String, program: &Vec<String>) -> String { - let mut pass = password.chars().collect::<VecDeque<_>>(); - - let instructions = scramble_instruction_set(); - - for line in program { - for &(ref reg, ref func) in &instructions { - let captures = reg.captures(line.as_ref()); - if captures.is_some() { - func(&mut pass, captures.unwrap()); - } - } - } - - pass.iter().cloned().collect() -} - -fn unscramble_password(password: String, program: &Vec<String>) -> String { - let mut pass = password.chars().collect::<VecDeque<_>>(); - - let instructions = unscramble_instruction_set(); - - let mut backwards_program = program.clone(); - backwards_program.reverse(); - for line in backwards_program { - for &(ref reg, ref func) in &instructions { - let captures = reg.captures(line.as_ref()); - if captures.is_some() { - func(&mut pass, captures.unwrap()); - } - } - } - - pass.iter().cloned().collect() -} - -fn scramble_instruction_set() -> Vec<(Regex, fn(&mut VecDeque<char>, regex::Captures))> { - let mut instructions : Vec<(Regex, fn(&mut VecDeque<char>, regex::Captures))> = Vec::new(); - instructions.push((Regex::new(r"swap position (\d+) with position (\d+)").unwrap(), swap_pos)); - instructions.push((Regex::new(r"swap letter ([a-z]) with letter ([a-z])").unwrap(), swap_let)); - instructions.push((Regex::new(r"rotate left (\d+) step").unwrap(), rotate_left)); - instructions.push((Regex::new(r"rotate right (\d+) step").unwrap(), rotate_right)); - instructions.push((Regex::new(r"rotate based on position of letter ([a-z])").unwrap(), rotate_pos)); - instructions.push((Regex::new(r"reverse positions (\d+) through (\d+)").unwrap(), reverse_sub)); - instructions.push((Regex::new(r"move position (\d+) to position (\d+)").unwrap(), move_pos)); - - instructions -} - -fn unscramble_instruction_set() -> Vec<(Regex, fn(&mut VecDeque<char>, regex::Captures))> { - let mut instructions : Vec<(Regex, fn(&mut VecDeque<char>, regex::Captures))> = Vec::new(); - instructions.push((Regex::new(r"swap position (\d+) with position (\d+)").unwrap(), swap_pos)); - instructions.push((Regex::new(r"swap letter ([a-z]) with letter ([a-z])").unwrap(), swap_let)); - instructions.push((Regex::new(r"rotate left (\d+) step").unwrap(), rotate_right)); - instructions.push((Regex::new(r"rotate right (\d+) step").unwrap(), rotate_left)); - instructions.push((Regex::new(r"rotate based on position of letter ([a-z])").unwrap(), undo_rotate_pos)); - instructions.push((Regex::new(r"reverse positions (\d+) through (\d+)").unwrap(), reverse_sub)); - instructions.push((Regex::new(r"move position (\d+) to position (\d+)").unwrap(), undo_move_pos)); - - instructions -} - -fn swap_pos(pass: &mut VecDeque<char>, cap: regex::Captures) { - let src = cap.at(1).unwrap().parse::<usize>().unwrap(); - let dest = cap.at(2).unwrap().parse::<usize>().unwrap(); - pass.swap(src, dest); -} - -fn swap_let(pass: &mut VecDeque<char>, cap: regex::Captures) { - let src = cap.at(1).unwrap().chars().next().unwrap(); - let dest = cap.at(2).unwrap().chars().next().unwrap(); - let src_position = pass.iter().position(|&c| c == src); - let dest_position = pass.iter().position(|&c| c == dest); - match (src_position, dest_position) { - (Some(src_pos), Some(dest_pos)) => { - pass.swap(src_pos, dest_pos); - }, - _ => {} - }; -} - -fn rotate_left(pass: &mut VecDeque<char>, cap: regex::Captures) { - let steps = cap.at(1).unwrap().parse::<usize>().unwrap(); - for _ in 0..steps { - let c = pass.pop_front().unwrap(); - pass.push_back(c); - } -} - -fn rotate_right(pass: &mut VecDeque<char>, cap: regex::Captures) { - let steps = cap.at(1).unwrap().parse::<usize>().unwrap(); - for _ in 0..steps { - let c = pass.pop_back().unwrap(); - pass.push_front(c); - } -} - -fn rotate_pos(pass: &mut VecDeque<char>, cap: regex::Captures) { - let letter = cap.at(1).unwrap().chars().next().unwrap(); - let pos = pass.iter().position(|&c| c == letter).unwrap(); - let steps = 1 + pos + if pos >=4 { 1 } else { 0 }; - for _ in 0..steps { - let c = pass.pop_back().unwrap(); - pass.push_front(c); - } -} - -fn move_pos(pass: &mut VecDeque<char>, cap: regex::Captures) { - let src = cap.at(1).unwrap().parse::<usize>().unwrap(); - let dest = cap.at(2).unwrap().parse::<usize>().unwrap(); - let c = pass.remove(src).unwrap(); - pass.insert(dest, c); -} - -fn reverse_sub(pass: &mut VecDeque<char>, cap: regex::Captures) { - let mut start = cap.at(1).unwrap().parse::<usize>().unwrap(); - let mut end = cap.at(2).unwrap().parse::<usize>().unwrap(); - while start < end { - pass.swap(start, end); - start += 1; - end -= 1; - } -} - -fn undo_rotate_pos(pass: &mut VecDeque<char>, cap: regex::Captures) { - let letter = cap.at(1).unwrap().chars().next().unwrap(); - let dest_pos = pass.iter().position(|&c| c == letter).unwrap(); - let mut pos = dest_pos; - - loop { - let c = pass.pop_front().unwrap(); - pass.push_back(c); - pos -= 1; - let steps = 1 + pos + if pos >=4 { 1 } else { 0 }; - if (pos + steps) % pass.len() == dest_pos { - break; - } - } -} - -fn undo_move_pos(pass: &mut VecDeque<char>, cap: regex::Captures) { - let src = cap.at(1).unwrap().parse::<usize>().unwrap(); - let dest = cap.at(2).unwrap().parse::<usize>().unwrap(); - let c = pass.remove(dest).unwrap(); - pass.insert(src, c); -} - -#[test] -fn swap_pos_example() { - let instructions = vec!("swap position 4 with position 0".to_string()); - let password = "abcde".to_string(); - assert_eq!("ebcda".to_string(), scramble_password(password, instructions)); -} - -#[test] -fn swap_let_example() { - let instructions = vec!("swap letter d with letter b".to_string()); - let password = "ebcda".to_string(); - assert_eq!("edcba".to_string(), scramble_password(password, instructions)); -} - -#[test] -fn reverse_example() { - let instructions = vec!("reverse positions 0 through 4".to_string()); - let password = "edcba".to_string(); - assert_eq!("abcde".to_string(), scramble_password(password, instructions)); -} - -#[test] -fn rotate_left_example() { - let instructions = vec!("rotate left 1 step".to_string()); - let password = "abcde".to_string(); - assert_eq!("bcdea".to_string(), scramble_password(password, instructions)); -} - -#[test] -fn move_example() { - let instructions = vec!("move position 3 to position 0".to_string()); - let password = "bdeac".to_string(); - assert_eq!("abdec".to_string(), scramble_password(password, instructions)); -} - -#[test] -fn rotate_pos_example_1() { - let instructions = vec!("rotate based on position of letter b".to_string()); - let password = "abdec".to_string(); - assert_eq!("ecabd".to_string(), scramble_password(password, instructions)); -} - -#[test] -fn rotate_pos_example_2() { - let instructions = vec!("rotate based on position of letter d".to_string()); - let password = "ecabd".to_string(); - assert_eq!("decab".to_string(), scramble_password(password, instructions)); -} - -#[test] -fn rotate_right_example() { - let instructions = vec!("rotate right 2 steps".to_string()); - let password = "decab".to_string(); - assert_eq!("abdec".to_string(), scramble_password(password, instructions)); -} |