Iterative solution for December 7th 2015

2015/7/iterative_wire.py

@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+import sys
+from pprint import pprint
+wires = {}
+instructions = [l.strip().split(' -> ') for l in sys.stdin.readlines()]
+instructions = [(instruction.split(' '), dest) for instruction, dest in instructions]
+
+def get_value(text):
+    if text.isdigit():
+        return int(text)
+    return wires.get(text)
+
+def parse(line):
+    words, dest = line
+    if len(words) == 1:
+        if words[0].isdigit() and dest in wires:
+            print('Ignoring redefinition of wire {} to {} (already set to {})'.format(
+                dest, words[0], wires[dest]))
+            return False
+        value = get_value(words[0])
+        if value is None:
+            return True
+        wires[dest] = value
+        return False
+    elif len(words) == 2 and words[0] == 'NOT':
+        value = get_value(words[1])
+        if value is None:
+            return True
+        wires[dest] = ~value & 0xffff
+        return False
+    elif len(words) == 3:
+        a, gate, b = words
+        a, b = get_value(a), get_value(b)
+        if a is None or b is None:
+            return True
+        if gate == 'AND':
+            wires[dest] = a & b
+        elif gate == 'OR':
+            wires[dest] = a | b
+        elif gate == 'LSHIFT':
+            wires[dest] = a << b
+        elif gate == 'RSHIFT':
+            wires[dest] = a >> b
+        else:
+            raise NotImplementedError
+        return False
+    else:
+        raise NotImplementedError
+
+def find_wire(name, data):
+    while name not in wires:
+        data = list(filter(parse, data))
+    return wires[name]
+
+part_one = find_wire('a', instructions)
+print('Part 1:', part_one)
+wires = {'b': part_one}
+part_two = find_wire('a', instructions)
+print('Part 2:', part_two)