package day01

import readInput

/**
 * Santa's reindeer typically eat regular reindeer food, but they need a lot of magical energy to deliver presents on Christmas.
 * For that, their favorite snack is a special type of star fruit that only grows deep in the jungle. The Elves have brought you on their annual expedition to the grove where the fruit grows.
 *
 * To supply enough magical energy, the expedition needs to retrieve a minimum of fifty stars by December 25th.
 * Although the Elves assure you that the grove has plenty of fruit, you decide to grab any fruit you see along the way, just in case.
 *
 * Collect stars by solving puzzles. Two puzzles will be made available on each day in the Advent calendar;
 * the second puzzle is unlocked when you complete the first. Each puzzle grants one star. Good luck!
 *
 * PART 1:
 * The jungle must be too overgrown and difficult to navigate in vehicles or access from the air; the Elves' expedition traditionally goes on foot.
 * As your boats approach land, the Elves begin taking inventory of their supplies. One important consideration is food - in particular, the number of Calories each Elf is carrying (your puzzle input).
 *
 * The Elves take turns writing down the number of Calories contained by the various meals, snacks, rations, etc.
 * that they've brought with them, one item per line. Each Elf separates their own inventory from the previous Elf's inventory (if any) by a blank line.
 *
 * For example, suppose the Elves finish writing their items' Calories and end up with the following list:
 *
 * 1000
 * 2000
 * 3000
 *
 * 4000
 *
 * 5000
 * 6000
 *
 * 7000
 * 8000
 * 9000
 *
 * 10000
 *
 * This list represents the Calories of the food carried by five Elves:
 *
 * The first Elf is carrying food with 1000, 2000, and 3000 Calories, a total of 6000 Calories.
 * The second Elf is carrying one food item with 4000 Calories.
 * The third Elf is carrying food with 5000 and 6000 Calories, a total of 11000 Calories.
 * The fourth Elf is carrying food with 7000, 8000, and 9000 Calories, a total of 24000 Calories.
 * The fifth Elf is carrying one food item with 10000 Calories.
 * In case the Elves get hungry and need extra snacks, they need to know which Elf to ask: they'd like to know how many Calories are being carried by the Elf carrying the most Calories. In the example above, this is 24000 (carried by the fourth Elf).
 *
 * Find the Elf carrying the most Calories. How many total Calories is that Elf carrying?
 *
 *
 * PART 2:
 * By the time you calculate the answer to the Elves' question, they've already realized that the Elf carrying the most Calories of food might eventually run out of snacks.
 *
 * To avoid this unacceptable situation, the Elves would instead like to know the total Calories carried by the top three Elves carrying the most Calories.
 * That way, even if one of those Elves runs out of snacks, they still have two backups.
 *
 * In the example above, the top three Elves are the fourth Elf (with 24000 Calories), then the third Elf (with 11000 Calories), then the fifth Elf (with 10000 Calories).
 * The sum of the Calories carried by these three elves is 45000.
 *
 * Find the top three Elves carrying the most Calories. How many Calories are those Elves carrying in total?
 */
private fun main() {
    fun part1(input: List<String>): Int {
        val result = mutableListOf(0)
        var currentElfIndex = 0

        input.forEach { line ->
            if (line.isEmpty()) {
                currentElfIndex++
                result.add(0)
            } else {
                result[currentElfIndex] += line.toInt()
            }
        }

        return result.max()
    }

    fun part2(input: List<String>): Int {
        val result = mutableListOf(0)
        var currentElfIndex = 0

        input.forEach { line ->
            if (line.isEmpty()) {
                currentElfIndex++
                result.add(0)
            } else {
                result[currentElfIndex] += line.toInt()
            }
        }

        val sorted = result.sortedDescending()

        return sorted[0] + sorted[1] + sorted[2]
    }

    val testInput = readInput("Day01_test")
    check(part1(testInput) == 24000)

    val input = readInput("Day01")
    println(part1(input))
    println(part2(input))
}
