46 lines
1.4 KiB
Kotlin
Executable File
46 lines
1.4 KiB
Kotlin
Executable File
#!/usr/bin/env kotlin
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import java.util.Scanner
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val scanner = Scanner(System.`in`)
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var total = 0L
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var totalTwo = 0L
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val operations = listOf("*", "+")
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while (scanner.hasNext()) {
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val line = scanner.nextLine()
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val (targetString, rest) = line.split(":", limit = 2).map { it.trim() }
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val target = targetString.toLong()
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val values = rest.split(Regex("""\s+""")).map { it.toLong() }
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if (hitsTarget(target, values, operations)) {
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total += target
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totalTwo += target
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} else if (hitsTarget(target, values, listOf("||") + operations)) {
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totalTwo += target
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}
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}
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println("Total result: $total")
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println("Total result (part 2): $totalTwo")
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fun hitsTarget(target: Long, values: List<Long>, operations: List<String>): Boolean {
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if (values.size == 1) {
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return target == values[0]
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}
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val (operandOne, operandTwo) = values.take(2)
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if (operandOne > target) {
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return false
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}
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val rest = values.drop(2)
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for (op in operations) {
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val result = when (op) {
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"+" -> operandOne + operandTwo
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"*" -> operandOne * operandTwo
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"||" -> "$operandOne$operandTwo".toLong()
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else -> throw IllegalArgumentException("Unknown operation: $op")
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}
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if (hitsTarget(target, listOf(result) + rest, operations)) {
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return true
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}
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}
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return false
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}
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