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| 1 | +package com.codefork.aoc2024.day24; |
| 2 | + |
| 3 | +import java.util.HashMap; |
| 4 | +import java.util.Map; |
| 5 | +import java.util.regex.Pattern; |
| 6 | +import java.util.stream.Stream; |
| 7 | + |
| 8 | +import static com.codefork.aoc2024.util.FoldLeft.foldLeft; |
| 9 | + |
| 10 | +public record Device(Map<String, Wire> namesToWires) { |
| 11 | + |
| 12 | + public sealed interface Wire permits And, Or, Xor, NamedValue, LiteralValue { |
| 13 | + int value(Device device); |
| 14 | + } |
| 15 | + |
| 16 | + public record LiteralValue(int value) implements Wire { |
| 17 | + |
| 18 | + @Override |
| 19 | + public int value(Device device) { |
| 20 | + return value; |
| 21 | + } |
| 22 | + } |
| 23 | + |
| 24 | + public record NamedValue(String name) implements Wire { |
| 25 | + |
| 26 | + @Override |
| 27 | + public int value(Device device) { |
| 28 | + return device.namesToWires().get(name).value(device); |
| 29 | + } |
| 30 | + } |
| 31 | + |
| 32 | + public record And(NamedValue op1, NamedValue op2) implements Wire { |
| 33 | + |
| 34 | + @Override |
| 35 | + public int value(Device device) { |
| 36 | + return op1.value(device) & op2.value(device); |
| 37 | + } |
| 38 | + } |
| 39 | + |
| 40 | + public record Or(NamedValue op1, NamedValue op2) implements Wire { |
| 41 | + |
| 42 | + @Override |
| 43 | + public int value(Device device) { |
| 44 | + return op1.value(device) | op2.value(device); |
| 45 | + } |
| 46 | + } |
| 47 | + |
| 48 | + public record Xor(NamedValue op1, NamedValue op2) implements Wire { |
| 49 | + |
| 50 | + @Override |
| 51 | + public int value(Device device) { |
| 52 | + return op1.value(device) ^ op2.value(device); |
| 53 | + } |
| 54 | + } |
| 55 | + |
| 56 | + private static final Pattern literalValuePat = Pattern.compile("(\\w{3}): (\\d)"); |
| 57 | + private static final Pattern gatePat = Pattern.compile("(\\w{3}) (AND|OR|XOR) (\\w{3}) -> (\\w{3})"); |
| 58 | + |
| 59 | + public static Device parse(Stream<String> data) { |
| 60 | + var namesToWires = data |
| 61 | + .filter(line -> !line.isEmpty()) |
| 62 | + .collect(foldLeft( |
| 63 | + () -> new HashMap<String, Wire>(), |
| 64 | + (acc, line) -> { |
| 65 | + var literalValueMatcher = literalValuePat.matcher(line); |
| 66 | + if(literalValueMatcher.find()) { |
| 67 | + var name = literalValueMatcher.group(1); |
| 68 | + var value = Integer.parseInt(literalValueMatcher.group(2)); |
| 69 | + acc.put(name, new LiteralValue(value)); |
| 70 | + return acc; |
| 71 | + } |
| 72 | + var gateMatcher = gatePat.matcher(line); |
| 73 | + if(gateMatcher.find()) { |
| 74 | + var op1 = new NamedValue(gateMatcher.group(1)); |
| 75 | + var op = gateMatcher.group(2); |
| 76 | + var op2 = new NamedValue(gateMatcher.group(3)); |
| 77 | + var name = gateMatcher.group(4); |
| 78 | + var wire = switch(op) { |
| 79 | + case "AND" -> new And(op1, op2); |
| 80 | + case "OR" -> new Or(op1, op2); |
| 81 | + case "XOR" -> new Xor(op1, op2); |
| 82 | + default -> throw new RuntimeException("unrecognized gate: " + op); |
| 83 | + }; |
| 84 | + acc.put(name, wire); |
| 85 | + return acc; |
| 86 | + } |
| 87 | + throw new RuntimeException("Couldn't parse line: " + line); |
| 88 | + }) |
| 89 | + ); |
| 90 | + return new Device(namesToWires); |
| 91 | + } |
| 92 | + |
| 93 | + public int getWire(String wireName) { |
| 94 | + return namesToWires.get(wireName).value(this); |
| 95 | + } |
| 96 | +} |
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