AdventOfCode/Rust/2023/09.rs

50 lines
924 B
Rust

#![feature(test)]
type Input = Vec<Vec<i32>>;
fn setup(input: &str) -> Input {
input
.lines()
.map(|line| {
line.split_whitespace()
.map(|x| x.parse().unwrap())
.collect()
})
.collect()
}
fn solve(mut nums: Vec<i32>) -> i32 {
for j in 1.. {
let mut all_zero = true;
let mut prev = nums[j - 1];
for i in nums.iter_mut().skip(j) {
*i = prev - *i;
prev -= *i;
all_zero &= *i == 0;
}
if all_zero {
break;
}
}
nums.into_iter().sum()
}
fn part1(input: &Input) -> i32 {
input
.clone()
.into_iter()
.map(|mut nums| {
nums.reverse();
solve(nums)
})
.sum()
}
fn part2(input: &Input) -> i32 {
input.clone().into_iter().map(solve).sum()
}
aoc::main!(2023, 9, ex: 1);