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extern crate crypto;
use std::collections::VecDeque;
use std::io::{self, Read};
use std::iter;
use crypto::digest::Digest;
use crypto::md5::Md5;
fn md5(salt: &str, index: u32) -> String {
let mut md5 = Md5::new();
md5.input_str(salt);
md5.input_str(&index.to_string());
md5.result_str()
}
fn solve(salt: &str) -> u32 {
let mut hashes = VecDeque::new();
for i in 0..1001 {
hashes.push_back(md5(salt, i));
}
let mut keys = 0;
let mut index = 0;
while let Some(hash) = hashes.pop_front() {
let triple = hash.as_bytes()
.windows(3)
.filter(|w| w[0] == w[1] && w[1] == w[2])
.map(|w| w[0])
.next();
if let Some(ch) = triple {
let quintuple: String = iter::repeat(ch as char).take(5).collect();
if hashes.iter().any(|hash| hash.contains(&quintuple)) {
keys += 1;
if keys == 64 {
return index;
}
}
}
index += 1;
hashes.push_back(md5(salt, 1000 + index));
}
unreachable!()
}
fn main() {
let mut input = String::new();
io::stdin().read_to_string(&mut input).unwrap();
println!("Part 1: {}", solve(input.trim()));
}
#[test]
#[ignore]
fn part1() {
assert_eq!(22728, solve("abc"));
}
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