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#![allow(dead_code)]
#![allow(unused_variables)]
#![allow(unused_mut)]
use std::fs::File;
use std::io::Read;
fn hash(s: &str) -> usize {
let mut h: usize = 0;
for b in s.bytes() {
h = ((h + (b as usize)) * 17) % 256;
}
h
}
#[derive(Debug, PartialEq, Clone)]
struct Lens {
name: String,
h: usize,
f: Option<usize>,
}
fn main() {
// let filename = "in/day15.ref";
let filename = "in/day15.pzl";
let mut f = File::open(filename).expect("cannot open file");
let mut content = String::new();
f.read_to_string(&mut content).expect("cannot read file");
let token = content.trim_end().split(',');
let mut ls: Vec<Lens> = Vec::new();
let mut res1: usize = 0;
for t in token {
res1 += hash(t);
if t.contains('=') {
let (n, f) = t.split_once('=').unwrap();
ls.push(Lens {
name: n.to_owned(),
h: hash(n),
f: Some(f.parse().unwrap()),
});
} else {
let n = t.trim_end_matches('-');
ls.push(Lens {
name: n.to_owned(),
h: hash(n),
f: None,
});
}
}
let mut hm: Vec<Vec<Lens>> = vec![[].to_vec(); 256];
for l in ls {
if let Some(f) = l.f {
let mut found = false;
for ll in 0..hm[l.h].len() {
if hm[l.h][ll].name == l.name {
hm[l.h][ll].f = l.f;
found = true;
break;
}
}
if !found {
hm[l.h].push(l);
}
} else {
hm[l.h].retain(|x| x.name != l.name);
}
}
let mut res2 = 0;
for b in 0..hm.len() {
for l in 0..hm[b].len() {
res2 += (b + 1) * (l + 1) * hm[b][l].f.unwrap();
}
}
println!("res1: {}", res1);
println!("res2: {}", res2);
assert_eq!(res1, 506437);
assert_eq!(res2, 288521);
}
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