31 lines
645 B
Kotlin
31 lines
645 B
Kotlin
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fun main() {
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val input = readInputString("day11.txt").split(" ").map { it.toLong() }
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val part1 = (1..25).fold(input) { result, _ ->
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result.blink()
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}.count()
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println("Part 1: $part1")
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val part2 = (1..75).fold(input) { result, _ ->
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result.blink()
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}.count()
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println("Part 2: $part2")
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}
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fun List<Long>.blink() = flatMap {
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val str = "$it"
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val strLen = str.count()
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when {
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it == 0L -> listOf(1L)
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strLen % 2 == 0 -> listOf(
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str.substring(0, strLen / 2).toLong(),
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str.substring(strLen / 2).toLong()
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)
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else -> listOf(it * 2024)
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}
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}
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