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use std::io::{self, Read};
fn reverse(ring: &mut Vec<u32>, index: usize, len: usize) {
for i in 0..(len / 2) {
let a = (index + i) % ring.len();
let b = (index + len - 1 - i) % ring.len();
let x = ring[a];
ring[a] = ring[b];
ring[b] = x;
}
}
fn hash(input: &str) -> Vec<u8> {
let mut ring: Vec<_> = (0..256).collect();
let mut index = 0;
let mut skip = 0;
let mut lens: Vec<_> = input.as_bytes().to_vec();
lens.extend(&[17, 31, 73, 47, 23]);
for _ in 0..64 {
for len in lens.iter().cloned() {
reverse(&mut ring, index, len as usize);
index += len as usize + skip;
index %= ring.len();
skip += 1;
}
}
ring.chunks(16)
.map(|chunk| chunk.iter().fold(0, |a, b| a ^ b))
.map(|x| x as u8)
.collect()
}
fn solve1(input: &str) -> u32 {
(0..128)
.map(|i| hash(&format!("{}-{}", input, i)))
.map(|h| h.into_iter().map(u8::count_ones).sum::<u32>())
.sum()
}
fn main() {
let mut input = String::new();
io::stdin().read_to_string(&mut input).unwrap();
println!("Part 1: {}", solve1(input.trim()));
}
#[test]
fn part1() {
assert_eq!(8108, solve1("flqrgnkx"));
}
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