Files
AdventOfCode2023/day09/src/main.rs
2023-12-11 09:52:06 -05:00

71 lines
2.0 KiB
Rust

use std::fs;
fn main() {
let input = fs::read_to_string("input.txt").unwrap();
let input: Vec<_> = input.split('\n')
.map(|line| {
line.split_whitespace()
.map(|num| num.parse::<i64>().unwrap())
.collect::<Vec<_>>()
}).collect();
let mut total = 0;
for line in input {
let mut line_starters: Vec<i64> = vec![*line.first().unwrap()];
let mut cur_line: Vec<i64> = line;
while !cur_line.iter().all(|x| *x == 0) {
let mut next_line: Vec<i64> = vec![];
for i in 1..cur_line.len() {
let diff = cur_line[i] - cur_line[i-1];
next_line.push(diff)
}
line_starters.push(*next_line.first().unwrap());
cur_line = next_line;
}
let mut sum = 0;
for i in (1..line_starters.len()).rev() {
sum = line_starters[i - 1] - sum;
}
total += sum;
}
println!("{:?}", total)
}
// use std::fs;
// fn main() {
// let input = fs::read_to_string("input.txt").unwrap();
// let input: Vec<_> = input.split('\n')
// .map(|line| {
// line.split_whitespace()
// .map(|num| num.parse::<i64>().unwrap())
// .collect::<Vec<_>>()
// }).collect();
// let mut total = 0;
// for line in input {
// let mut line_enders: Vec<i64> = vec![*line.last().unwrap()];
// let mut cur_line: Vec<i64> = line;
// while !cur_line.iter().all(|x| *x == 0) {
// let mut next_line: Vec<i64> = vec![];
// for i in 1..cur_line.len() {
// let diff = cur_line[i] - cur_line[i-1];
// next_line.push(diff)
// }
// line_enders.push(*next_line.last().unwrap());
// cur_line = next_line;
// }
// let mut sum = 0;
// for i in (1..line_enders.len()).rev() {
// sum = sum + line_enders[i - 1];
// }
// total += sum;
// }
// println!("{:?}", total)
// }