62 lines
1.5 KiB
Rust
62 lines
1.5 KiB
Rust
|
use std::collections::HashMap;
|
||
|
|
use std::fs;
|
||
|
|
|
||
|
|
struct Node {
|
||
|
|
left: String,
|
||
|
|
right: String,
|
||
|
|
}
|
||
|
|
|
||
|
|
fn main() {
|
||
|
|
// let file_contents = fs::read_to_string("sample.txt").expect("No input found");
|
||
|
|
let file_contents = fs::read_to_string("input.txt").expect("No input found");
|
||
|
|
let mut lines = file_contents.lines();
|
||
|
|
|
||
|
|
let steps = lines.next().expect("No steps found");
|
||
|
|
let map = lines
|
||
|
|
.filter(|l| !l.is_empty())
|
||
|
|
.map(|l| {
|
||
|
|
let node = &l[0..3];
|
||
|
|
let left = &l[7..10];
|
||
|
|
let right = &l[12..15];
|
||
|
|
|
||
|
|
(
|
||
|
|
node,
|
||
|
|
Node {
|
||
|
|
left: left.to_string(),
|
||
|
|
right: right.to_string(),
|
||
|
|
},
|
||
|
|
)
|
||
|
|
})
|
||
|
|
.collect::<HashMap<&str, Node>>();
|
||
|
|
|
||
|
|
let mut current = map
|
||
|
|
.keys()
|
||
|
|
.filter(|node| node.ends_with("A"))
|
||
|
|
.map(|node| node.clone())
|
||
|
|
.collect::<Vec<&str>>();
|
||
|
|
|
||
|
|
for node in ¤t {
|
||
|
|
println!("Starting node {}", node);
|
||
|
|
}
|
||
|
|
|
||
|
|
let mut num_steps = 0;
|
||
|
|
for step in steps.chars().cycle() {
|
||
|
|
if current.iter().all(|node| node.ends_with("Z")) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
num_steps += 1;
|
||
|
|
|
||
|
|
for i in 0..current.len() {
|
||
|
|
if step == 'L' {
|
||
|
|
current[i] = &map[current[i]].left;
|
||
|
|
}
|
||
|
|
if step == 'R' {
|
||
|
|
current[i] = &map[current[i]].right;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
println!("Part 2 {}", num_steps)
|
||
|
|
}
|