34 lines
721 B
Text
34 lines
721 B
Text
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import java.util.Scanner
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val isSafelyIncreasing = { offset: Int -> offset in 1..3 }
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val isSafelyDecreasing = { offset: Int -> offset in (-3)..(-1) }
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fun isSafeRoute(levels: List<Int>): Boolean {
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val levelOffsets = levels.foldIndexed(ArrayList<Int>()) { index, acc, i ->
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if (index > 0) {
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acc.add(i - levels[index - 1])
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}
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acc
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}
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return levelOffsets.all(isSafelyIncreasing) || levelOffsets.all(isSafelyDecreasing)
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}
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val scanner = Scanner(System.`in`)
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var safeCount = 0
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while (scanner.hasNextInt()) {
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val line = scanner.nextLine()
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val numbers = line.split(" ").map { it.toInt() }
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if (isSafeRoute(numbers)) {
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safeCount++
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}
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}
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println(safeCount)
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