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