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day24.js Raw
1/**
2 * @typedef {object} Sequence
3 * @property {string[]} inputs
4 * @property {string} gate
5 * @property {string} output
6 */
7
8/**
9 * @param {Sequence[]} sequence
10 * @returns {Sequence[]}
11 */
12const sort = (sequence) => {
13 const sequenceObj = {};
14
15 for (const next of sequence) {
16 sequenceObj[next.output] = next;
17 }
18
19 const seen = new Set();
20 const stack = [];
21
22 /** @param {string} wire */
23 const topologicalSort = (wire) => {
24 if (!seen.has(wire)) {
25 seen.add(wire);
26 const r1 = sequenceObj[wire].inputs[0];
27 const r2 = sequenceObj[wire].inputs[1];
28 if (r1 in sequenceObj) topologicalSort(r1);
29 if (r2 in sequenceObj) topologicalSort(r2);
30 stack.push(wire);
31 }
32 }
33
34 for (const wire in sequenceObj) {
35 topologicalSort(wire);
36 }
37
38 return stack.filter(wire => wire in sequenceObj).map(wire => sequenceObj[wire]);
39}
40
41/**
42 * @param {string} input
43 * @returns {System}
44 */
45const parseInput = (input) => {
46 const [initialValues, sequenceLines] = input.split(/\r?\n\r?\n/g).map(v => v.split(/\r?\n/g).filter(v => v.length > 0));
47 const system = new System();
48 initialValues.forEach((v) => {
49 const [register, value] = v.split(': ');
50 system.registers[register] = parseInt(value);
51 });
52
53 system.sequence = sort(sequenceLines.map(v => {
54 const [r1, gate, r2, _, r3] = v.split(' ');
55 return {
56 inputs: [r1, r2],
57 gate,
58 output: r3,
59 };
60 }));
61
62 return system;
63}
64
65class System {
66 /** @type {Record<string, number>} */
67 registers = {};
68 /** @type {Sequence[]} */
69 sequence = [];
70
71 static gates = {
72 AND(i1, i2) {
73 return i1 & i2;
74 },
75 OR(i1, i2) {
76 return i1 | i2;
77 },
78 XOR(i1, i2) {
79 return i1 ^ i2;
80 }
81 };
82
83 /**
84 * @param {Record<string, number>} registers
85 * @param {string} designation
86 * @returns {string}
87 */
88 static readRegisterBinary(registers, designation) {
89 return Object.keys(registers)
90 .filter(k => k.startsWith(designation))
91 .sort((a, b) => parseInt(a.slice(1)) - parseInt(b.slice(1)))
92 .reduce((a, k) => a = `${registers[k]}${a}`, '')
93 }
94
95 /**
96 * Simulate the logic running and return the output.
97 * @returns {number}
98 */
99 simulate() {
100 const sequence = this.sequence.map(r => ({ ...r }));
101 const registers = { ...this.registers };
102 for (const next of sequence) {
103 const { inputs, gate, output } = next;
104
105 registers[output] = System.gates[gate](registers[inputs[0]], registers[inputs[1]]);
106 }
107 return parseInt(System.readRegisterBinary(registers, 'z'), 2);
108 }
109}
110
111const input = require('fs').readFileSync(0, 'utf-8');
112const system = parseInput(input);
113
114console.log('Part One:', system.simulate());
115
116const swapRand = () => {
117 const rSwaps = [];
118
119 while (true) {
120 if (rSwaps.length === 8) break;
121 const rNext = Math.floor(Math.random() * (system.sequence.length))
122 if (!rSwaps.includes(rNext)) {
123 rSwaps.push(rNext);
124 }
125 }
126
127 const swapGroups = [rSwaps.slice(0, 2), rSwaps.slice(2, 4), rSwaps.slice(4, 6), rSwaps.slice(6, 8)];
128
129 const sequenceBackup = system.sequence.map(r => ({ ...r }));
130 const swaps = [];
131 for (const [r1, r2] of swapGroups) {
132 const v1 = system.sequence[r1].output;
133 const v2 = system.sequence[r2].output;
134 system.sequence[r1].output = v2;
135 system.sequence[r2].output = v1;
136 swaps.push(v1, v2);
137 }
138
139 system.sequence = sort(system.sequence);
140
141 const out = system.simulate();
142 system.sequence = sequenceBackup;
143 return {
144 out,
145 swaps: [...swaps].sort(),
146 orig: swaps
147 };
148}
149
150const x = System.readRegisterBinary(system.registers, 'x');
151const y = System.readRegisterBinary(system.registers, 'y');
152const expected = parseInt(x, 2) + parseInt(y, 2);
153
154const logger = new class {
155 ops = 0;
156 lOps = 0;
157 lOpsTs = new Date().getTime();
158 incrOps() {
159 const curTs = new Date().getTime();
160 if (curTs - this.lOpsTs >= 1000) {
161 this.lOps = this.ops;
162 this.ops = 0;
163 this.lOpsTs = curTs;
164 }
165 this.ops += 1;
166 }
167
168 last = 0;
169 write(lastOut, force) {
170 const curTs = new Date().getTime();
171 if (force === true || curTs - this.last > 250) {
172 process.stdout.clearLine(1);
173 process.stdout.cursorTo(0);
174 const parts = [];
175 parts.push(`ops/s=${this.lOps}`);
176 parts.push(`last_out=${lastOut}`);
177 process.stdout.write(parts.join(' '));
178 this.last = curTs;
179 }
180 }
181}
182
183console.log();
184while (true) {
185 logger.incrOps()
186 const { out, swaps, orig } = swapRand();
187 if (out === expected) {
188 process.stdout.clearLine(1);
189 process.stdout.cursorTo(0);
190 process.stdout.write(`Match: ${swaps.join(',')} [${orig.join(',')}]\n`);
191 process.stdout.write('\n');
192 }
193 logger.write(swaps.join(','));
194}