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#![allow(dead_code)]
#![allow(unused_variables)]
#![allow(unused_mut)]
use std::collections::HashMap;
use std::env;
use std::fs::File;
use std::io::Read;
fn evolve(s: &Vec<u64>) -> Vec<u64> {
let mut sn: Vec<u64> = Vec::new();
for n in s {
if *n == 0 {
sn.push(1);
} else if n.checked_ilog(10).unwrap() % 2 == 1 {
let pow = 10_u64.pow(n.checked_ilog(10).unwrap() / 2 + 1);
sn.push(n / pow);
sn.push(n % pow);
} else {
sn.push(n * 2024);
}
}
return sn;
}
fn evolve_fast(n: u64, depth: u64, lut: &mut HashMap<(u64, u64), u64>) -> u64 {
if depth == 0 {
return 1;
}
if let Some(val) = lut.get(&(n, depth)) {
return *val;
}
let val = if n == 0 {
evolve_fast(1, depth - 1, lut)
} else if n.checked_ilog(10).unwrap() % 2 == 1 {
let pow = 10_u64.pow(n.checked_ilog(10).unwrap() / 2 + 1);
let a = evolve_fast(n / pow, depth - 1, lut);
let b = evolve_fast(n % pow, depth - 1, lut);
a + b
} else {
evolve_fast(n * 2024, depth - 1, lut)
};
lut.insert((n, depth), val);
return val;
}
fn main() {
let args: Vec<String> = env::args().collect();
let filename = if args.len() == 1 {
"in/".to_owned() + args[0].split('/').last().unwrap() + ".pzl"
} else {
args[1].clone()
};
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 line = content.trim_end().split("\n").next().unwrap();
let stones: Vec<u64> = line.split(" ").map(|a| a.parse().unwrap()).collect();
let mut s = stones.clone();
for i in 0..25 {
s = evolve(&s);
}
let res1 = s.len();
let mut s2 = stones.clone();
let mut res2 = 0;
let mut lut = HashMap::new();
for n in s2 {
res2 += evolve_fast(n, 75, &mut lut);
}
println!("res1: {}", res1);
println!("res2: {}", res2);
assert_eq!(res1, 220722);
assert_eq!(res2, 261952051690787);
}
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