60 lines
2.2 KiB
Plaintext
60 lines
2.2 KiB
Plaintext
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#!/usr/bin/env kotlin
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import java.util.Scanner
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import java.util.PriorityQueue
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val scanner = Scanner(System.`in`)
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class PriorityCache<K, V>(private val maxSize: Int) {
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private val cache = mutableMapOf<K, V>()
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private val priorityQueue = PriorityQueue<Pair<K, Int>>(compareBy { it.second }) // Pair(Key, Priority)
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fun put(key: K, value: V, priority: Int) {
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if (cache.size >= maxSize) {
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val leastPriority = priorityQueue.poll() // Remove the lowest-priority item
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cache.remove(leastPriority.first)
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}
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cache[key] = value
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priorityQueue.add(Pair(key, priority))
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}
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fun get(key: K): V? {
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return cache[key]
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}
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fun isCached(key: K): Boolean {
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return cache.containsKey(key)
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}
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}
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val priorityCache = PriorityCache<String, Int>(20000)
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fun getStonesAfter(input: List<Int>,iterations: Int, cache: PriorityCache<String, Int>): Int {
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return input.fold(0) { acc, i -> acc + getStoneNumber(i, iterations, cache) }
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}
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fun getStoneNumber(number: Int, iterations: Int, cache: PriorityCache<String, Int>): Int {
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if (iterations == 0) {
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return 1
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} else if (cache.isCached("$iterations-$number")) {
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return cache.get("$iterations-$number")!!
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} else if (number == 0) {
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val stonesum = getStonesAfter(listOf(3), iterations - 1, cache)
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cache.put("$iterations-0", stonesum, iterations)
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return stonesum
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} else if (number.toString().length % 2 == 0) {
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val mid = number.toString().length / 2
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val left = number.toString().substring(0, mid).toInt()
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val right = number.toString().substring(mid).toInt()
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val stonesum = getStoneNumber(left, iterations - 1, cache) + getStoneNumber(right, iterations - 1, cache)
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cache.put("$iterations-$number", stonesum, iterations)
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return stonesum
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} else {
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val newVal = number * 2024
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val stonesum = getStoneNumber(newVal, iterations - 1, cache)
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cache.put("$iterations-$number", stonesum, iterations)
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return stonesum
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}
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}
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val input = scanner.nextLine().split(" ").map { it.toInt() }
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println("First part with 25 iterations: ${getStonesAfter(input, 25, priorityCache)}")
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