advent-of-code-2021/1/src/main.rs

55 lines
1.4 KiB
Rust

use std::fs;
fn main() {
// part_1();
part_2();
}
fn part_1() {
let contents = fs::read_to_string("./input").expect("Couldn't read file!");
let numbers: Vec<usize> = contents
.lines()
.map(|s| s.parse::<usize>().unwrap())
.collect();
let initial_condition: (usize, usize) = (0, 1000000);
let increases = numbers.iter().fold(initial_condition, |acc, num| {
if num > &acc.1 {
(acc.0 + 1, *num)
} else {
(acc.0, *num)
}
});
println!("{}", increases.0);
}
fn part_2() {
let contents = fs::read_to_string("./input").expect("Couldn't read file!");
let numbers: Vec<usize> = contents
.lines()
.map(|s| s.parse::<usize>().unwrap())
.collect();
// inc n - 3 n - 2 n - 1
let initial_condition: (usize, (usize, usize, usize)) = (0, (0, 0, 0));
let increases = numbers.iter().fold(initial_condition, |acc, num| {
let new_previous_numbers = (acc.1 .1, acc.1 .2, *num);
if acc.1 .0 == 0 {
return (0, new_previous_numbers);
}
let previous_sum = acc.1 .0 + acc.1 .1 + acc.1 .2;
let current_sum = acc.1 .1 + acc.1 .2 + num;
if current_sum > previous_sum {
(acc.0 + 1, new_previous_numbers)
} else {
(acc.0, new_previous_numbers)
}
});
println!("{}", increases.0);
}