From d1c0ec56ded915d92bd7307efdfdfff233ad52cd Mon Sep 17 00:00:00 2001
From: Daniel Seiller <earthnuker@gmail.com>
Date: Mon, 7 Dec 2020 14:04:31 +0100
Subject: [PATCH] Day 7

---
 src/day7.rs | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs  |  1 +
 2 files changed, 80 insertions(+)
 create mode 100644 src/day7.rs

diff --git a/src/day7.rs b/src/day7.rs
new file mode 100644
index 0000000..0cfaa7e
--- /dev/null
+++ b/src/day7.rs
@@ -0,0 +1,79 @@
+use aoc_runner_derive::{aoc, aoc_generator};
+use std::collections::{HashMap, HashSet, VecDeque};
+
+pub struct Data {
+    fwd: HashMap<String, Vec<(usize, String)>>,
+    rev: HashMap<String, Vec<(usize, String)>>,
+}
+
+impl Data {
+    pub fn new() -> Data {
+        Data {
+            fwd: HashMap::new(),
+            rev: HashMap::new(),
+        }
+    }
+}
+
+#[aoc_generator(day7)]
+pub fn input_generator(input: &str) -> Data {
+    let mut ret = Data::new();
+    for line in input.lines() {
+        let mut line = line.to_owned();
+        line = line.replace("contain", "");
+        line = line.replace("bags", "");
+        line = line.replace("bag", "");
+        line = line.replace(",", "");
+        line = line.replace(".", "");
+        while line.contains("  ") {
+            line = line.replace("  ", " ");
+        }
+        line = line.trim().to_owned();
+        let mut l: VecDeque<String> = line
+            .split_ascii_whitespace()
+            .map(|s| s.to_owned())
+            .collect();
+        let outer_color: String = [l.pop_front().unwrap(), l.pop_front().unwrap()].join(" ");
+        while let (Some(n), Some(c1), Some(c2)) = (l.pop_front(), l.pop_front(), l.pop_front()) {
+            let n: usize = n.parse().unwrap();
+            let inner_color = vec![c1.to_owned(), c2.to_owned()].join(" ");
+            ret.fwd
+                .entry(outer_color.clone())
+                .or_default()
+                .push((n, inner_color.clone()));
+            ret.rev
+                .entry(inner_color.clone())
+                .or_default()
+                .push((n, outer_color.clone()));
+        }
+    }
+    ret
+}
+
+#[aoc(day7, part1)]
+pub fn solve_part1(input: &Data) -> usize {
+    let mut cnt = 0;
+    let mut q = VecDeque::new();
+    q.push_back("shiny gold".to_owned());
+    while let Some(c) = q.pop_front() {
+        for (_, nc) in input.rev.get(&c).iter().map(|v| v.iter()).flatten() {
+            cnt += 1;
+            q.push_back(nc.clone());
+        }
+    }
+    return cnt;
+}
+
+#[aoc(day7, part2)]
+pub fn solve_part2(input: &Data) -> usize {
+    let mut cnt = 0;
+    let mut q = VecDeque::new();
+    q.push_back((1, "shiny gold".to_owned()));
+    while let Some((o_n, c)) = q.pop_front() {
+        for (n, nc) in input.fwd.get(&c).iter().map(|v| v.iter()).flatten() {
+            cnt += n * o_n;
+            q.push_back((n * o_n, nc.clone()));
+        }
+    }
+    return cnt;
+}
diff --git a/src/lib.rs b/src/lib.rs
index 349216a..b9a72e2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,4 +5,5 @@ pub mod day3;
 pub mod day4;
 pub mod day5;
 pub mod day6;
+pub mod day7;
 aoc_lib! { year = 2020 }