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105 lines
2.7 KiB
105 lines
2.7 KiB
use std::char;
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use std::cmp::Ordering;
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use std::collections::HashMap;
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use errors::*;
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use regex::Regex;
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pub fn solve(input: &str) -> Result<String> {
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let rooms: Vec<(Room, String)> = input.lines()
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.map(|line| {
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let re = Regex::new(r"(?P<room>.+)\[(?P<checksum>.+)\]").unwrap();
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let caps = re.captures(line).ok_or("")?;
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let room = caps.name("room").unwrap();
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let checksum = caps.name("checksum").unwrap();
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Room::new(room).map(|room| (room, checksum.into()))
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})
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.collect::<Result<_>>()?;
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let mut real_rooms = rooms.iter()
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.filter(|&&(ref room, ref checksum)| room.checksum() == *checksum)
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.map(|&(ref room, _)| room);
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let room = real_rooms.find(|room| room.name().contains("north")).ok_or("")?;
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Ok(room.sector_id.to_string())
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}
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#[test]
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fn test_solve() {}
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struct Room {
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encrypted_name: String,
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sector_id: usize,
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}
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impl Room {
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fn new(s: &str) -> Result<Self> {
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let re = Regex::new(r"(?P<name>.+)-(?P<id>\d+)").unwrap();
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let caps = re.captures(s).ok_or("")?;
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let name = caps.name("name").unwrap();
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let id = caps.name("id").unwrap().parse().chain_err(|| "")?;
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Ok(Room {
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encrypted_name: name.into(),
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sector_id: id,
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})
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}
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fn checksum(&self) -> String {
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let mut counts = HashMap::new();
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for c in self.encrypted_name.chars().filter(|c| c.is_alphabetic()) {
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*counts.entry(c).or_insert(0) += 1;
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}
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let mut counts: Vec<_> = counts.iter().collect();
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counts.sort_by(|a, b| {
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match b.1.cmp(a.1) {
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Ordering::Equal => a.0.cmp(b.0),
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x => x,
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}
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});
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counts.iter().take(5).map(|x| *x.0).collect()
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}
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fn name(&self) -> String {
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self.encrypted_name.chars().map(|c| {
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match c {
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'-' => ' ',
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c => {
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let digit = c.to_digit(36).unwrap() - 10;
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let shifted = (digit + self.sector_id as u32) % 26;
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char::from_digit(shifted + 10, 36).unwrap()
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},
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}
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}).collect()
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}
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}
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#[test]
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fn test_new() {
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let room = Room::new("aaaaa-bbb-z-y-x-123").unwrap();
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assert_eq!(room.encrypted_name, "aaaaa-bbb-z-y-x".to_string());
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assert_eq!(room.sector_id, 123);
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}
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#[test]
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fn test_checksum() {
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let room = Room::new("aaaaa-bbb-z-y-x-123").unwrap();
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assert_eq!(room.checksum(), "abxyz".to_string());
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let room = Room::new("a-b-c-d-e-f-g-h-987").unwrap();
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assert_eq!(room.checksum(), "abcde".to_string());
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let room = Room::new("not-a-real-room-404").unwrap();
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assert_eq!(room.checksum(), "oarel".to_string());
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let room = Room::new("totally-real-room-200").unwrap();
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assert_ne!(room.checksum(), "decoy".to_string());
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}
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#[test]
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fn test_name() {
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let room = Room::new("qzmt-zixmtkozy-ivhz-343").unwrap();
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assert_eq!(room.name(), "very encrypted name");
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}
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