154 lines
4.1 KiB
TypeScript
154 lines
4.1 KiB
TypeScript
const fs = require('fs');
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const input = fs.readFileSync(__dirname + '/input.txt', 'utf8');
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const [initStr, gatesStr] = input.split("\n\n");
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const originalValMap: { [key: string]: number }= {};
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let valMap: { [key: string]: number } = {};
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const gateMap: { [key: string]: [string, string, string] } = {};
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let xStr = '';
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let yStr = '';
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const outputWires: Array<string> = [];
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initStr.split("\n").forEach((s: string) => {
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const [wire, val] = s.split(': ');
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originalValMap[wire] = parseInt(val, 2);
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if (wire.startsWith('x')) {
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xStr += val;
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} else {
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yStr += val;
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}
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});
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valMap = {...originalValMap};
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const carries: Array<string> = [];
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const halfAdds: Array<string> = [];
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const badOuts: Array<string> = [];
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const badAnds: Array<string> = [];
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const gates: Array<[string, string, string, string]> = gatesStr.split("\n").map((s: string) => {
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const [inp, out] = s.split(' -> ');
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const [val1, op, val2] = inp.split(' ');
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return [val1, op, val2, out];
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});
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gates.forEach(([val1, op, val2, out]) => {
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gateMap[out] = [val1, op, val2];
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if (out.startsWith('z')) {
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outputWires.push(out);
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}
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if ((op === 'XOR' && !val1.startsWith('x') && !val1.startsWith('y')) || (op === 'XOR' && (val1 === 'x00' || val1 === 'y00'))) {
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if (!out.startsWith('z')) {
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badOuts.push(out);
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}
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} else if (out.startsWith('z')) {
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badOuts.push(out);
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}
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if (op === 'AND') {
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for (let [val1, op, val2] of gates) {
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if (op !== 'OR' && (val1 === out || val2 === out)) {
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badAnds.push(out);
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break;
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}
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}
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}
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});
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function getWireVal(wire: string, trace: Array<string> = []): number {
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if (Object.hasOwn(valMap, wire)) {
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return valMap[wire];
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}
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const [wire1, op, wire2] = gateMap[wire];
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if (trace.includes(wire1) || trace.includes(wire2)) {
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throw Error('Cycle');
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}
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const val = getVal(wire1, op, wire2, [...trace, wire1, wire2]);
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valMap[wire] = val;
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return val;
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}
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function getVal(wire1: string, op: string, wire2: string, trace: Array<string> = []): number {
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const val1 = getWireVal(wire1, trace);
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const val2 = getWireVal(wire2, trace);
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return {
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AND: () => val1 & val2,
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OR: () => val1 | val2,
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XOR: () => val1 ^ val2,
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}[op]!();
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}
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outputWires.sort().reverse();
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function calculate() {
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let outputStr = '';
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valMap = {...originalValMap};
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outputWires.forEach((wire) => {
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outputStr += getWireVal(wire);
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});
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return outputStr;
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}
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function getPermutations(arr: Array<string>): Array<Array<string>> {
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if (arr.length === 1) {
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return [arr];
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}
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return arr.flatMap((s, i) => {
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return getPermutations([...arr.slice(0, i), ...arr.slice(i + 1)]).map((p) => [s, ...p]);
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});
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}
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function swap(wire1: string, wire2: string): void {
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const wire1Gate = gateMap[wire1];
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const wire2Gate = gateMap[wire2];
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gateMap[wire1] = wire2Gate;
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gateMap[wire2] = wire1Gate;
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}
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const expected = (parseInt(xStr, 2) + parseInt(yStr, 2)).toString(2);
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const zOutputsToSwap = badOuts.filter((o) => o[0] === 'z');
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const otherOutputsToSwap = badOuts.filter((o) => o[0] !== 'z');
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for (let perm of getPermutations(zOutputsToSwap)) {
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swap(perm[0], otherOutputsToSwap[0]);
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swap(perm[1], otherOutputsToSwap[1]);
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swap(perm[2], otherOutputsToSwap[2]);
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for (let i = 0; i < gates.length - 1; i++) {
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for (let j = i + 1; j < gates.length; j++) {
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swap(gates[i][3], gates[j][3]);
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try {
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const output = calculate();
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if (output === expected) {
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const swaps = [...perm, ...otherOutputsToSwap, gates[i][3], gates[j][3]];
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swaps.sort();
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console.log(swaps);
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break;
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}
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} catch (e) {
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//
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} finally {
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swap(gates[i][3], gates[j][3]);
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}
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}
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}
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swap(perm[0], otherOutputsToSwap[0]);
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swap(perm[1], otherOutputsToSwap[1]);
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swap(perm[2], otherOutputsToSwap[2]);
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}
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/*
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* 1234
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* 4123
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* 3412
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* 2341
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* 4321
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* 1432
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* 2143
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* 3214
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* 1324
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* 4132
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*/ |