2017/06-07

2017/07/Cargo.lock

@@ -0,0 +1,4 @@
+[[package]]
+name = "day-07"
+version = "0.1.0"
+

2017/07/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "day-07"
+version = "0.1.0"
+authors = ["logaritmisk <anders.e.olsson@gmail.com>"]
+
+[dependencies]

2017/07/example.txt

@@ -0,0 +1,13 @@
+pbga (66)
+xhth (57)
+ebii (61)
+havc (66)
+ktlj (57)
+fwft (72) -> ktlj, cntj, xhth
+qoyq (66)
+padx (45) -> pbga, havc, qoyq
+tknk (41) -> ugml, padx, fwft
+jptl (61)
+ugml (68) -> gyxo, ebii, jptl
+gyxo (61)
+cntj (57)

2017/07/src/main.rs

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+use std::io::{self, Read};
+
+
+mod parser {
+    pub type Program<'a> = (&'a str, i64, Vec<&'a str>);
+
+
+    #[derive(Clone, Copy)]
+    enum State {
+        Name,
+        PreWeight,
+        Weight(usize),
+        PreAbove,
+        Above(usize),
+    }
+
+
+    pub fn from_str(input: &str) -> Program {
+        let mut name = None;
+        let mut weight = None;
+        let mut above = Vec::new();
+
+        let mut state = State::Name;
+
+        for (i, c) in input.chars().enumerate() {
+            match (state, c) {
+                (State::Name, ' ') => {
+                    name = Some(&input[0..i]);
+                    state = State::PreWeight;
+                }
+
+                (State::PreWeight, '(') => {
+                    state = State::Weight(i + 1);
+                }
+
+                (State::Weight(start), ')') => {
+                    weight = input[start..i].parse::<i64>().ok();
+                    state = State::PreAbove;
+                }
+
+                (State::PreAbove, 'a'...'z') => {
+                    state = State::Above(i);
+                }
+
+                (State::Above(start), ',') => {
+                    above.push(&input[start..i]);
+                    state = State::PreAbove;
+                }
+
+                _ => (),
+            }
+        }
+
+        if let State::Above(start) = state {
+            above.push(&input[start..input.len()]);
+        }
+
+        (name.unwrap(), weight.unwrap(), above)
+    }
+}
+
+mod tree {
+    use std::collections::{HashMap, VecDeque};
+
+    use parser::Program;
+
+
+    pub type Tree<'a> = HashMap<&'a str, Info<'a>>;
+
+
+    #[derive(Debug)]
+    pub struct Info<'a> {
+        weight: i64,
+        above: Tree<'a>,
+    }
+
+
+    pub fn build(programs: Vec<Program>) -> Tree {
+        let mut tree = Tree::new();
+
+        let mut temp = VecDeque::new();
+
+        for (name, weight, above) in programs {
+            if above.is_empty() {
+                tree.insert(
+                    name,
+                    Info {
+                        weight: weight,
+                        above: Tree::new(),
+                    },
+                );
+            } else {
+                temp.push_back((name, weight, above));
+            }
+        }
+
+        while let Some((name, weight, above)) = temp.pop_front() {
+            if above
+                .iter()
+                .any(|name_above| !tree.contains_key(name_above))
+            {
+                temp.push_back((name, weight, above));
+
+                continue;
+            }
+
+            let info = Info {
+                weight: weight,
+                above: above
+                    .into_iter()
+                    .map(|name_above| (name_above, tree.remove(name_above).unwrap()))
+                    .collect::<Tree>(),
+            };
+
+            tree.insert(name, info);
+        }
+
+        tree
+    }
+
+    pub fn stacker(name: &str, root: &Info, level: usize) -> i64 {
+        if root.above.is_empty() {
+            root.weight
+        } else {
+            let mut total = 0;
+            let mut map = HashMap::new();
+
+            for (name, stack) in &root.above {
+                let weight = stacker(name, stack, level + 1);
+
+                total += weight;
+
+                map.entry(weight).or_insert_with(Vec::new).push(name);
+            }
+
+            if map.len() > 1 {
+                let (wrong, correct) =
+                    map.iter()
+                        .fold((0, 0), |(wrong, correct), (weight, programs)| {
+                            if programs.len() == 1 {
+                                (*weight, correct)
+                            } else {
+                                (wrong, *weight)
+                            }
+                        });
+
+                let mut weight = root.above[map[&wrong][0]].weight;
+
+                weight += correct - wrong;
+
+                println!("{}: {} weight should be {}", level, name, weight);
+            }
+
+            root.weight + total
+        }
+    }
+
+}
+
+
+fn main() {
+    let mut input = String::new();
+
+    io::stdin()
+        .read_to_string(&mut input)
+        .expect("failed to read input");
+
+    let programs = input
+        .lines()
+        .filter(|line| !line.is_empty())
+        .map(parser::from_str)
+        .collect::<Vec<_>>();
+
+    let tree = tree::build(programs);
+
+    let root = tree.keys().nth(0).unwrap();
+
+    println!("part_one={:?}", root);
+    println!("part_two:");
+
+    tree::stacker(root, &tree[root], 0);
+}
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_parse() {
+        assert_eq!(parser::from_str("pbga (66)"), ("pbga", 66, vec![]));
+        assert_eq!(
+            parser::from_str("fwft (72) -> ktlj, cntj, xhth"),
+            ("fwft", 72, vec!["ktlj", "cntj", "xhth"])
+        );
+    }
+}