25 lines
448 B
Text
25 lines
448 B
Text
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import java.util.Scanner
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val scanner = Scanner(System.`in`)
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val listLeft = ArrayList<Int>()
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val listRight = ArrayList<Int>()
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while (scanner.hasNextInt()) {
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val num1 = scanner.nextInt()
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listLeft.add(num1)
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val num2 = scanner.nextInt()
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listRight.add(num2)
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}
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val rightFrequencies = listRight.groupingBy { it }.eachCount()
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val sum = listLeft.fold(0, { sum, left ->
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sum + left * (rightFrequencies[left] ?: 0)
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})
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println(sum)
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