59 lines
1.5 KiB
TypeScript
59 lines
1.5 KiB
TypeScript
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const fs = require('fs');
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const input = fs.readFileSync(__dirname + '/input.txt', 'utf8');
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function createSecret(secret: bigint) {
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secret = ((secret << 6n) ^ secret) % 16777216n;
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secret = ((secret >> 5n) ^ secret) % 16777216n;
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return ((secret << 11n) ^ secret) % 16777216n;
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}
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let sum = 0n;
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const changeMap: { [key: string]: Array<number> } = {};
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input.split("\n").forEach((s: string, index: number) => {
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let seed = BigInt(parseInt(s));
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let seedStr = ''+seed;
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const changes = [];
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for (let i = 0; i < 2000; i++) {
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const newSeed = createSecret(seed);
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const newSeedStr = ''+newSeed;
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const lastDig = parseInt(newSeedStr[newSeedStr.length - 1]);
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const diff = lastDig - parseInt(seedStr[seedStr.length - 1]);
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changes.push(diff);
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if (i > 3) {
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changes.shift();
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const key = changes.join(',');
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if (!changeMap[key]) {
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changeMap[key] = [];
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}
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if (!changeMap[key][index]) {
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changeMap[key][index] = lastDig;
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}
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}
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seed = newSeed;
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seedStr = newSeedStr;
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}
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sum += seed;
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});
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let highest: null|number = null;
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let highestSeq: null|string = null;
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for (let seq in changeMap) {
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const prices = changeMap[seq];
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let priceSum = 0;
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prices.forEach((p) => {
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if (p) {
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priceSum += p;
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}
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});
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if (!highest || priceSum > highest) {
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highest = priceSum;
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highestSeq = seq;
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}
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}
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console.log(sum, highest, highestSeq);
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