43 lines
1 KiB
JavaScript
43 lines
1 KiB
JavaScript
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const input = (await Bun.file(Bun.argv[2]).text()).trim()
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const stones = input.split(" ").map(num => parseInt(num))
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const splits = num => countDigits(num) % 2 == 0;
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const countDigits = num => Math.floor(Math.log10(num)) + 1;
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const getLeft = num => Math.floor(num / Math.pow(10, countDigits(num) / 2));
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const getRight = num => num - getLeft(num) * Math.pow(10, countDigits(num) / 2);
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const memo = new Map();
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const blinkTimes = (times, num) => {
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if (times == 0) return 1;
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const key = times + '*' + num;
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if (memo.has(key)) {
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return memo.get(key)
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}
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let result
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if (num === 0) {
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result = blinkTimes(times-1, 1)
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} else if (splits(num)) {
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result = blinkTimes(times-1, getLeft(num)) + blinkTimes(times-1, getRight(num))
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} else {
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result = blinkTimes(times-1, num * 2024)
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}
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memo.set(key, result)
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return result;
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}
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let count = 0
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for (const stone of stones) {
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count += blinkTimes(25, stone)
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}
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console.log("part 1", count)
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count = 0
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for (const stone of stones) {
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count += blinkTimes(75, stone)
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}
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console.log("part 2", count)
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