23 lines
771 B
Kotlin
23 lines
771 B
Kotlin
package be.vandewalleh.aoc.days
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import be.vandewalleh.aoc.utils.input.Day
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import be.vandewalleh.aoc.utils.input.Lines
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@Day(2)
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class Day02(@Lines input: List<String>) {
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private data class PasswordEntry(val range: IntRange, val letter: Char, val password: String)
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private val regex = "^(\\d+)-(\\d+) ([a-z]): (.*)$".toRegex()
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private val passwords = input.map {
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val (_, min, max, letter, password) = regex.find(it)!!.groupValues
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PasswordEntry(min.toInt()..max.toInt(), letter[0], password)
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}
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fun part1() = passwords.count { it.password.count { char -> char == it.letter } in it.range }
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fun part2() = passwords.count { (range, letter, pwd) ->
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(pwd[range.first - 1] == letter) xor (pwd[range.last - 1] == letter)
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}
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}
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