From a201f57d1303aa22940c2c6694ae4e587b51c58a Mon Sep 17 00:00:00 2001
From: Jordan Doyle <jordan@doyle.la>
Date: Mon, 30 Dec 2024 01:00:15 +0700
Subject: [PATCH] Add 2024 day 24

---
 README     |  4 ++--
 2024/24.py | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/README b/README
index fc532e3..3a908fe 100644
--- a/README
+++ a/README
@@ -37,6 +37,6 @@
 |       21 | Rust     | |       21 | Rust     |
 |       22 | Rust     | |       22 | Haskell  |
 |       23 | Python   | |       23 | Haskell  |
-+---------------------+ |       24 | Haskell  |
-                        |       25 | Bash     |
+|       24 | Python   | |       24 | Haskell  |
++---------------------+ |       25 | Bash     |
                         +---------------------+
diff --git a/2024/24.py b/2024/24.py
new file mode 100755
index 0000000..082ef40 100755
--- /dev/null
+++ a/2024/24.py
@@ -1,0 +1,74 @@
+#! /usr/bin/env nix-shell
+#! nix-shell -i python3 -p python3Packages.pillow python3Packages.networkx
+
+import sys
+import networkx as nx
+
+[unparsed_states, operations] = "".join(sys.stdin.readlines()).strip().split("\n\n")
+
+states = dict([(state.split(": ")[0], state.split(": ")[1] != "0") for state in unparsed_states.strip().split("\n")])
+parsed_operations = []
+
+G = nx.DiGraph()
+
+for operation in operations.strip().split("\n"):
+    [deps, out] = operation.split(' -> ')
+    [left, oper, right] = deps.split(' ')
+    G.add_node(left)
+    G.add_node(right)
+    G.add_node(out, oper = oper)
+    G.add_edge(left, out)
+    G.add_edge(right, out)
+
+    parsed_operations.append((left, oper, right, out))
+
+top_level_nodes = [node for node in G.nodes() if G.in_degree(node) == 0]
+topo = [v for v in (nx.topological_sort(G)) if v not in top_level_nodes]
+visited = set()
+
+for node in topo:
+    if node in visited:
+        continue
+
+    visited.add(node)
+    
+    [a, b] = [a for [a, _] in G.in_edges(node)]
+    operation = G.nodes[node]["oper"]
+
+    if operation == "XOR":
+        states[node] = states[a] ^ states[b]
+    elif operation == "OR":
+        states[node] = states[a] or states[b]
+    elif operation == "AND":
+        states[node] = states[a] and states[b]
+
+part1 = 0
+
+for i, key in enumerate([key for key in sorted(states.keys()) if key.startswith('z')]):
+    part1 |= states[key] << i
+
+print(part1)
+
+part2 = []
+
+lowest_bit = [key for key in sorted(states.keys()) if key.startswith('z')][-1]
+output_rails = ["x", "y", "z"]
+
+for left, oper, right, out in parsed_operations:
+    is_non_xor_z_output = out[0] == "z" and oper != "XOR" and out != lowest_bit
+    is_invalid_and = oper == "AND" and "x00" not in (left, right) and any(
+        out in (left_, right_) and oper_ != "OR"
+        for left_, oper_, right_, out_ in parsed_operations
+    )
+    is_invalid_xor = oper == "XOR" and (
+        all(v[0] not in output_rails for v in (left, right, out)) or 
+        any(out in (left_, right_) and oper_ == "OR" 
+            for left_, oper_, right_, out_ in parsed_operations)
+    )
+
+    if is_non_xor_z_output or is_invalid_and or is_invalid_xor:
+        part2.append(out)
+        
+
+print(','.join(sorted(part2)))
+
--
rgit 0.1.5