Advent of code day 9

nine.rs

use std::collections::VecDeque;
use std::fs::File;
use std::io::{self, BufRead};

const PREAMBLE_LENGTH: usize = 25;

fn has_sum_makers(sum: u64, preamble: Vec<u64>) -> bool {
    assert_eq!(preamble.len(), PREAMBLE_LENGTH);
    for a in &preamble {
        for b in &preamble {
            if a + b == sum {
                return true;
            }
        }
    }
    false
}

fn find_false_property(numbers: &Vec<u64>) -> u64 {
    for x in PREAMBLE_LENGTH..numbers.len() {
        let val = *numbers.get(x).unwrap();
        let preamble: Vec<_> = numbers
            .to_vec()
            .splice(x - PREAMBLE_LENGTH..x, vec![])
            .collect();
        if !has_sum_makers(val, preamble) {
            return val;
        }
    }
    0
}

fn main() {
    let file = File::open("input.txt").unwrap();
    let lines: Vec<u64> = io::BufReader::new(file)
        .lines()
        .map(|line| line.unwrap().parse::<u64>().unwrap())
        .collect();
    let false_property = find_false_property(&lines);
    println!("First: {}", false_property);

    let mut acc = VecDeque::new();
    for number in lines {
        acc.push_back(number);
        while acc.iter().sum::<u64>() > false_property {
            acc.pop_front();
        }

        let sum = acc.iter().sum::<u64>();
        if sum == false_property {
            let small = acc.iter().min().unwrap();
            let max = acc.iter().max().unwrap();
            println!("Second: {}", small + max);
            break;
        }
    }
}