2021 Day8

    val data = """<<INPUT HERE>>""".split("\n").map { it.split(" | ").map { a-> a.split(" ") }}

    private val String.sorted: String
        get() = this.toSortedSet().joinToString("")

    @Test
    fun `Part 1`() {
        val lengthsToCount = listOf(2,3,4,7)
        println(data[1].sumBy { it.count { segments -> segments.length in lengthsToCount } })
    }

    @Test
    fun `Part 2`() {
        val sum = data.map {
            val numbers = extractAllNumbers(it[0].toMutableList())
            it[1].map { segments -> numbers [segments.sorted]}.fold(0) {output, number -> output * 10 + number!! }
        }.sum()
        println("Part 2: $sum")
    }

    private fun extractAllNumbers(numbers: MutableList<String>): Map<String, Int> {
        val one = numbers.find { it.length == 2 }!!; numbers -= one
        val four = numbers.find { it.length == 4 }!!; numbers -= four
        val seven = numbers.find { it.length == 3 }!!; numbers -= seven
        val eight = numbers.find { it.length == 7 }!!; numbers -= eight
        val nine = numbers.find { nine ->
            val nineChars = nine.chars().toList(); four.chars().allMatch { nineChars.contains(it) }
        }!!; numbers -= nine
        val zero = numbers.find { zero ->
            val zeroChars = zero.chars().toList(); zero.length == 6 && one.chars().allMatch { zeroChars.contains(it) }
        }!!; numbers -= zero
        val six = numbers.find { it.length == 6 }!!; numbers -= six
        val three = numbers.find { three ->
            val threeChars = three.chars().toList(); one.chars().allMatch { threeChars.contains(it) }
        }!!; numbers -= three
        val five = numbers.find { five ->
            val twoChars = five.chars(); twoChars.allMatch {
            six.chars().toList().contains(it)
        }
        }!!; numbers -= five
        val two = numbers[0]

        return listOf(
            one.sorted to 1,
            two.sorted to 2,
            three.sorted to 3,
            four.sorted to 4,
            five.sorted to 5,
            six.sorted to 6,
            seven.sorted to 7,
            eight.sorted to 8,
            nine.sorted to 9,
            zero.sorted to 0
        ).toMap()
    }