From 85e033f369571a2a4d84be56266df84dcdda556c Mon Sep 17 00:00:00 2001
From: Wesley Moore <wes@wezm.net>
Date: Sun, 22 Dec 2019 15:12:47 +1100
Subject: [PATCH] Day 14 part 1

---
 2019/input/day14.txt  | 63 ++++++++++++++++++++++++++++
 2019/src/bin/day14.rs | 97 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 160 insertions(+)
 create mode 100644 2019/input/day14.txt
 create mode 100644 2019/src/bin/day14.rs

diff --git a/2019/input/day14.txt b/2019/input/day14.txt
new file mode 100644
index 0000000..481d206
--- /dev/null
+++ b/2019/input/day14.txt
@@ -0,0 +1,63 @@
+10 KVPH => 5 HPRK
+5 RSTBJ => 5 QKBQL
+2 GZWFN, 21 WBPFQ => 5 KMFWH
+5 JDJB, 1 FSWFT, 1 NKVSV => 6 MGKSL
+5 BCRHK => 9 KXFTL
+23 NKVSV, 2 RSTBJ => 9 QPBVD
+19 BKFVS, 7 JZBFT => 7 XWTQ
+14 JLXP, 4 LSCL => 8 FWLTD
+173 ORE => 5 TZSDV
+2 FPVH, 1 JDJB, 3 KHRW => 2 QLNJ
+1 HTGMX, 1 GVJVK, 2 RLRK => 2 HWBM
+1 GLVHT, 1 PBCT, 5 ZWKGV, 1 QSVJ, 2 FWLTD, 3 CNVPB, 1 QGNL => 8 RNLTX
+1 KXZTS => 2 BKFVS
+1 KVPH, 6 PVHPV, 2 TZSDV => 4 RLRK
+118 ORE => 1 VRVZ
+7 MGKSL, 4 HWBM => 2 GZWFN
+5 PVHPV => 7 HTGMX
+25 LSCL, 12 GVMFW => 6 ZWKGV
+1 CTPND, 1 KXZTS => 3 FRQH
+1 KXFTL => 3 PBCT
+1 CMPX => 4 KZNBL
+2 HDQVB, 1 QPBVD => 5 CTPND
+14 KVPH => 1 FCBQN
+3 XWTQ, 22 CTHM, 4 KVPH, 4 BZTV, 1 KMFWH, 12 NRFK => 7 CXVR
+1 GVJVK => 7 RSTBJ
+1 GVJVK => 4 NSQHW
+3 NKVSV => 8 KHRW
+8 HDQVB, 9 BCRHK => 6 GVMFW
+142 ORE => 7 KVPH
+4 TZSDV => 2 GVJVK
+4 KVPH, 10 HWBM => 3 NRFK
+47 PBCT, 15 CXVR, 45 GVJVK, 23 KZNBL, 1 WFPNP, 14 RNLTX => 1 FUEL
+1 PCBNG => 4 QLJXM
+1 SHTQF => 2 FNWBZ
+2 FCBQN, 1 BCRHK => 5 HVFBV
+1 BZTQ => 9 CTHM
+16 SHTQF => 3 BZTQ
+11 PBCT, 5 PCBNG, 2 CTPND => 1 WBPFQ
+3 KHRW => 4 FSWFT
+12 HDQVB, 1 PBCT, 9 NRFK => 9 VLWJL
+5 SHTQF, 8 HVFBV => 6 BZTV
+2 KZNBL, 7 NRFK => 3 DVFS
+18 HTLSF, 14 DVFS => 6 TLFNL
+1 RSTBJ => 1 NKVSV
+2 QLNJ, 7 BZTQ => 6 PCBNG
+1 HTLSF, 19 CMPX => 7 JDJB
+6 KZNBL, 3 QSVJ => 8 SHTQF
+3 HTLSF, 1 VRVZ => 6 CMPX
+1 MGKSL, 15 CTPND => 6 STNPH
+2 NKVSV, 7 JDJB => 4 KXZTS
+3 KVPH => 4 QSVJ
+1 HPRK, 9 PCBNG, 2 KXFTL => 9 CNVPB
+27 GZWFN, 1 VLWJL, 15 LSCL => 3 GLVHT
+162 ORE => 4 HTLSF
+193 ORE => 8 PVHPV
+9 TLFNL, 1 KHRW => 6 HDQVB
+6 QLJXM, 4 FCBQN => 7 JLXP
+3 HTLSF, 21 NSQHW, 18 GVJVK => 7 BCRHK
+1 HTGMX, 20 CMPX, 6 RSTBJ => 6 FPVH
+4 KXZTS, 7 CNVPB, 1 STNPH => 2 LSCL
+3 KXZTS, 1 PCBNG => 3 JZBFT
+22 WBPFQ, 22 FRQH, 1 QLNJ, 4 CTHM, 3 GVMFW, 1 KMFWH, 4 QKBQL => 4 WFPNP
+3 QLJXM, 11 FNWBZ, 3 WBPFQ => 5 QGNL
diff --git a/2019/src/bin/day14.rs b/2019/src/bin/day14.rs
new file mode 100644
index 0000000..d804001
--- /dev/null
+++ b/2019/src/bin/day14.rs
@@ -0,0 +1,97 @@
+use std::collections::HashMap;
+use std::{fs, io};
+
+#[derive(Debug)]
+struct Material<'a> {
+    name: &'a str,
+    amount: usize,
+}
+
+#[derive(Debug)]
+struct Reaction<'a> {
+    inputs: Vec<Material<'a>>,
+    output: Material<'a>,
+}
+
+fn main() -> io::Result<()> {
+    let input = fs::read_to_string("input/day14.txt")?;
+    let reactions = parse_input(&input);
+
+    println!("Day 1 part 1: {}", ore_required(&reactions));
+
+    Ok(())
+}
+
+fn parse_input(input: &str) -> Vec<Reaction> {
+    input
+        .lines()
+        .map(|line| {
+            let mut io = line.trim().split(" => ");
+            let input = io.next().unwrap();
+            let output = io.next().map(parse_material).unwrap();
+            let inputs = input.split(", ").map(parse_material).collect();
+
+            Reaction { inputs, output }
+        })
+        .collect()
+}
+
+fn parse_material(s: &str) -> Material {
+    let mut parts = s.split_whitespace();
+    Material {
+        amount: parts.next().and_then(|amount| amount.parse().ok()).unwrap(),
+        name: parts.next().unwrap(),
+    }
+}
+
+fn ore_required(reactions: &[Reaction]) -> usize {
+    // Find FUEL and work back to ORE to find paths?
+    let map = reactions
+        .iter()
+        .map(|reaction| (reaction.output.name, reaction))
+        .collect::<HashMap<_, _>>();
+
+    let mut inventory = HashMap::new();
+    run_reaction("FUEL", &map, &mut inventory);
+    inventory.get("ORE").copied().unwrap_or_default().abs() as usize
+}
+
+// Run the named reaction, updating the inventory
+fn run_reaction<'a>(
+    name: &'a str,
+    tree: &'a HashMap<&'a str, &'a Reaction>,
+    inventory: &mut HashMap<&'a str, isize>,
+) {
+    let node = tree[name];
+    node.inputs.iter().for_each(|input| {
+        if input.name == "ORE" {
+            *inventory.entry("ORE").or_default() -= input.amount as isize;
+        } else {
+            *inventory.entry(input.name).or_default() -= input.amount as isize;
+            while inventory.get(input.name).copied().unwrap_or_default() < 0 {
+                run_reaction(input.name, tree, inventory);
+            }
+        }
+    });
+    *inventory.entry(name).or_default() += node.output.amount as isize;
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_small_example() {
+        let input = "9 ORE => 2 A
+8 ORE => 3 B
+7 ORE => 5 C
+3 A, 4 B => 1 AB
+5 B, 7 C => 1 BC
+4 C, 1 A => 1 CA
+2 AB, 3 BC, 4 CA => 1 FUEL
+";
+        let reactions = parse_input(&input);
+
+        assert_eq!(ore_required(&reactions), 165);
+    }
+}