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use std::io;
use std::io::BufRead;
use std::collections::HashMap;
use std::cmp::max;
use regex::Regex;
use lazy_static::lazy_static;
#[derive(PartialEq, Eq, PartialOrd, Ord)]
enum Action {
Begin(i32),
Sleep,
Wake
}
#[derive(PartialEq, Eq, PartialOrd, Ord)]
struct Record {
year: i32,
month: i32,
day: i32,
hour: i32,
minute: i32,
action: Action
}
struct Guard {
id: i32,
sleep_times: Vec<(i32, i32)>, // inclusive-exclusive
asleep: [i32; 60]
}
fn parse_action(line: &str) -> Action {
if line.chars().next() == Some('G') {
let idx = 7 + line[7..].find(' ').unwrap();
Action::Begin(line[7 .. idx].parse().unwrap())
} else if line.chars().next() == Some('f') {
Action::Sleep
} else {
Action::Wake
}
}
fn parse_line(line: &str) -> Record {
lazy_static! {
static ref RE: Regex = Regex::new(r"^\[(\d+)-(\d+)-(\d+) (\d+):(\d+)\] (.*)$").unwrap();
}
let caps = RE.captures(line).unwrap();
Record {
year: caps.get(1).unwrap().as_str().parse().unwrap(),
month: caps.get(2).unwrap().as_str().parse().unwrap(),
day: caps.get(3).unwrap().as_str().parse().unwrap(),
hour: caps.get(4).unwrap().as_str().parse().unwrap(),
minute: caps.get(5).unwrap().as_str().parse().unwrap(),
action: parse_action(caps.get(6).unwrap().as_str())
}
}
fn argmax<T: Ord>(v: &[T]) -> Option<usize> {
if v.len() == 0 {
None
} else {
let mut maxat = 0;
for i in 1..v.len() {
if v[i] > v[maxat] {
maxat = i;
}
}
Some(maxat)
}
}
pub fn main<T: BufRead>(reader: T) -> io::Result<(String, String)> {
let mut records: Vec<Record> = reader.lines().map(|l| parse_line(&l.unwrap())).collect();
records.sort_unstable();
let mut guards = HashMap::new();
{
let mut current_id = 0;
let mut sleep_start = 0;
for record in records.iter() {
match record.action {
Action::Begin(id) => {
if let None = guards.get(&id) {
guards.insert(id, Guard {id: id, sleep_times: Vec::new(), asleep: [0; 60]});
}
current_id = id;
},
Action::Sleep => sleep_start = record.minute,
Action::Wake =>
guards.get_mut(¤t_id).unwrap()
.sleep_times.push((sleep_start, record.minute))
}
}
}
let mut max_sleep = -1;
let mut max_sleep_at = -1;
let mut max_times = -1;
let mut max_times_at = -1;
for mut guard in guards.values_mut() {
let mut sleep = 0;
let mut times = 0;
for (from, to) in guard.sleep_times.iter() {
for i in *from..*to {
guard.asleep[i as usize] += 1;
times = max(times, guard.asleep[i as usize]);
}
sleep += to - from;
}
if sleep > max_sleep {
max_sleep = sleep;
max_sleep_at = guard.id;
}
if times > max_times {
max_times = times;
max_times_at = guard.id;
}
}
let sleepy_guard = guards.get(&max_sleep_at).unwrap();
let max_minute = argmax(&sleepy_guard.asleep).unwrap() as i32;
let part1 = max_minute * sleepy_guard.id;
let consistent_guard = guards.get(&max_times_at).unwrap();
let max_minute = argmax(&consistent_guard.asleep).unwrap() as i32;
let part2 = max_minute * consistent_guard.id;
Ok((part1.to_string(), part2.to_string()))
}
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