diff options
Diffstat (limited to '2017/src/bin/day_7.rs')
-rw-r--r-- | 2017/src/bin/day_7.rs | 62 |
1 files changed, 62 insertions, 0 deletions
diff --git a/2017/src/bin/day_7.rs b/2017/src/bin/day_7.rs new file mode 100644 index 0000000..3c3b185 --- /dev/null +++ b/2017/src/bin/day_7.rs @@ -0,0 +1,62 @@ +extern crate advent_of_code_2017; +use advent_of_code_2017::*; + +extern crate regex; +use regex::Regex; + +fn main() { + let args = AdventArgs::init(); + + let names_re = Regex::new(r"[a-z]+").unwrap(); + let weight_re = Regex::new(r"\d+").unwrap(); + + let tree: Vec<(String, Vec<String>, i32)> = args.input.iter() + .map(|line| { + let mut matches = names_re.find_iter(line); + let base = matches.next().unwrap().as_str().to_string(); + let leaves = matches.map(|m| m.as_str().to_string()).collect(); + let weight = weight_re.find(line).unwrap().as_str().parse().unwrap(); + (base, leaves, weight) + }).collect(); + + let mut possible_roots: Vec<String> = tree.iter().map(|&(ref id, _, _)| id.clone()).collect(); + for &(_, ref leaves, _) in &tree { + for leaf in leaves { + let index = possible_roots.iter().position(|x| x == leaf).unwrap(); + possible_roots.remove(index); + } + } + let root = &possible_roots[0]; + + if args.part == 1 { + println!("{:?}", root); + } else { + find_unweighted_plate(&root, &tree); + } +} + +fn find_unweighted_plate(root: &String, tree: &Vec<(String, Vec<String>, i32)>) -> i32 { + let root_node = find_node(&root, &tree); + let &(_, ref leaves, ref weight) = root_node; + let leaf_weights: Vec<i32> = leaves.iter().map(|leaf| { + find_unweighted_plate(&leaf, &tree) + }).collect(); + + if let Some(base_leaf_weight) = leaf_weights.first() { + if let Some(different_leaf_weight) = leaf_weights.iter().find(|&w| w != base_leaf_weight) { + println!("Unbalanced plate is off by {}", (different_leaf_weight-base_leaf_weight).abs()); + println!("Towers on plate: {:?} weigh {:?}", leaves, leaf_weights); + // This still needs some manual work to get to the puzzle + // output. Take the first unbalanced plate, figure out + // which is the unbalanced tower visually, find its + // individual weight in the file, and add/subtract as + // necessary. + } + } + + leaf_weights.iter().sum::<i32>() + weight +} + +fn find_node<'a>(name: &String, tree: &'a Vec<(String, Vec<String>, i32)>) -> &'a (String, Vec<String>, i32) { + tree.iter().find(|&&(ref id, _, _)| id == name).unwrap() +} |