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Commit 501e562

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Solved Day 21 part 2 (2015) - RPG Simulator 20XX
1 parent 0ab3e7c commit 501e562

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1 file changed

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  • src/main/java/com/sbaars/adventofcode/year15/days

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Lines changed: 196 additions & 17 deletions
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package com.sbaars.adventofcode.year15.days;
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import com.sbaars.adventofcode.year15.Day2015;
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import java.util.*;
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import java.util.stream.Collectors;
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public class Day21 extends Day2015 {
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public Day21() {
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super(21);
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}
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public static void main(String[] args) {
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new Day21().printParts();
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}
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@Override
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public Object part1() {
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return "";
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}
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@Override
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public Object part2() {
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return "";
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}
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private static final int PLAYER_HP = 100;
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private static final List<Item> WEAPONS = Arrays.asList(
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new Item("Dagger", 8, 4, 0),
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new Item("Shortsword", 10, 5, 0),
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new Item("Warhammer", 25, 6, 0),
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new Item("Longsword", 40, 7, 0),
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new Item("Greataxe", 74, 8, 0)
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);
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private static final List<Item> ARMOR = Arrays.asList(
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new Item("Leather", 13, 0, 1),
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new Item("Chainmail", 31, 0, 2),
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new Item("Splintmail", 53, 0, 3),
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new Item("Bandedmail", 75, 0, 4),
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new Item("Platemail", 102, 0, 5)
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);
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private static final List<Item> RINGS = Arrays.asList(
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new Item("Damage +1", 25, 1, 0),
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new Item("Damage +2", 50, 2, 0),
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new Item("Damage +3", 100, 3, 0),
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new Item("Defense +1", 20, 0, 1),
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new Item("Defense +2", 40, 0, 2),
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new Item("Defense +3", 80, 0, 3)
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);
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private record Item(String name, int cost, int damage, int armor) {}
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private record Character(int hp, int damage, int armor) {}
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private record Equipment(Item weapon, Item armor, Item ring1, Item ring2) {
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public int getTotalCost() {
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return weapon.cost() +
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(armor != null ? armor.cost() : 0) +
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(ring1 != null ? ring1.cost() : 0) +
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(ring2 != null ? ring2.cost() : 0);
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}
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public int getTotalDamage() {
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return weapon.damage() +
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(armor != null ? armor.damage() : 0) +
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(ring1 != null ? ring1.damage() : 0) +
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(ring2 != null ? ring2.damage() : 0);
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}
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public int getTotalArmor() {
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return (armor != null ? armor.armor() : 0) +
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(ring1 != null ? ring1.armor() : 0) +
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(ring2 != null ? ring2.armor() : 0);
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}
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}
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public Day21() {
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super(21);
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}
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public static void main(String[] args) {
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Day21 day = new Day21();
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day.printParts();
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new com.sbaars.adventofcode.network.Submit().submit(day.part2(), 2015, 21, 2);
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}
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@Override
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public Object part1() {
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Character boss = parseBoss();
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return findMinGoldToWin(boss);
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}
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@Override
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public Object part2() {
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Character boss = parseBoss();
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return findMaxGoldToLose(boss);
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}
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private Character parseBoss() {
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List<String> lines = dayStream().collect(Collectors.toList());
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int hp = Integer.parseInt(lines.get(0).split(": ")[1]);
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int damage = Integer.parseInt(lines.get(1).split(": ")[1]);
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int armor = Integer.parseInt(lines.get(2).split(": ")[1]);
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return new Character(hp, damage, armor);
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}
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private int findMinGoldToWin(Character boss) {
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int minGold = Integer.MAX_VALUE;
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// Try all possible equipment combinations
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for (Item weapon : WEAPONS) {
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// Try with no armor and no rings
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minGold = Math.min(minGold, tryEquipment(weapon, null, null, null, boss));
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// Try with armor but no rings
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for (Item armor : ARMOR) {
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minGold = Math.min(minGold, tryEquipment(weapon, armor, null, null, boss));
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}
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// Try with one ring, no armor
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for (Item ring1 : RINGS) {
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minGold = Math.min(minGold, tryEquipment(weapon, null, ring1, null, boss));
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}
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// Try with two rings, no armor
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for (int i = 0; i < RINGS.size(); i++) {
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for (int j = i + 1; j < RINGS.size(); j++) {
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minGold = Math.min(minGold, tryEquipment(weapon, null, RINGS.get(i), RINGS.get(j), boss));
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}
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}
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// Try with armor and one ring
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for (Item armor : ARMOR) {
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for (Item ring1 : RINGS) {
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minGold = Math.min(minGold, tryEquipment(weapon, armor, ring1, null, boss));
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}
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}
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// Try with armor and two rings
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for (Item armor : ARMOR) {
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for (int i = 0; i < RINGS.size(); i++) {
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for (int j = i + 1; j < RINGS.size(); j++) {
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minGold = Math.min(minGold, tryEquipment(weapon, armor, RINGS.get(i), RINGS.get(j), boss));
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}
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}
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}
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}
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return minGold;
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}
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private int tryEquipment(Item weapon, Item armor, Item ring1, Item ring2, Character boss) {
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Equipment equipment = new Equipment(weapon, armor, ring1, ring2);
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Character player = new Character(PLAYER_HP, equipment.getTotalDamage(), equipment.getTotalArmor());
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return simulateFight(player, boss) ? equipment.getTotalCost() : Integer.MAX_VALUE;
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}
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private boolean simulateFight(Character player, Character boss) {
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int playerDamagePerTurn = Math.max(1, player.damage() - boss.armor());
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int bossDamagePerTurn = Math.max(1, boss.damage() - player.armor());
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// Player goes first, so they need to kill the boss in equal or fewer turns
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int turnsToKillBoss = (boss.hp() + playerDamagePerTurn - 1) / playerDamagePerTurn;
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int turnsToKillPlayer = (player.hp() + bossDamagePerTurn - 1) / bossDamagePerTurn;
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return turnsToKillBoss <= turnsToKillPlayer;
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}
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private int findMaxGoldToLose(Character boss) {
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int maxGold = 0;
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// Try all possible equipment combinations
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for (Item weapon : WEAPONS) {
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// Try with no armor and no rings
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maxGold = Math.max(maxGold, tryEquipmentToLose(weapon, null, null, null, boss));
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// Try with armor but no rings
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for (Item armor : ARMOR) {
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maxGold = Math.max(maxGold, tryEquipmentToLose(weapon, armor, null, null, boss));
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}
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// Try with one ring, no armor
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for (Item ring1 : RINGS) {
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maxGold = Math.max(maxGold, tryEquipmentToLose(weapon, null, ring1, null, boss));
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}
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// Try with two rings, no armor
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for (int i = 0; i < RINGS.size(); i++) {
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for (int j = i + 1; j < RINGS.size(); j++) {
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maxGold = Math.max(maxGold, tryEquipmentToLose(weapon, null, RINGS.get(i), RINGS.get(j), boss));
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}
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}
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// Try with armor and one ring
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for (Item armor : ARMOR) {
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for (Item ring1 : RINGS) {
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maxGold = Math.max(maxGold, tryEquipmentToLose(weapon, armor, ring1, null, boss));
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}
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}
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// Try with armor and two rings
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for (Item armor : ARMOR) {
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for (int i = 0; i < RINGS.size(); i++) {
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for (int j = i + 1; j < RINGS.size(); j++) {
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maxGold = Math.max(maxGold, tryEquipmentToLose(weapon, armor, RINGS.get(i), RINGS.get(j), boss));
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}
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}
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}
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}
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return maxGold;
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}
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private int tryEquipmentToLose(Item weapon, Item armor, Item ring1, Item ring2, Character boss) {
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Equipment equipment = new Equipment(weapon, armor, ring1, ring2);
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Character player = new Character(PLAYER_HP, equipment.getTotalDamage(), equipment.getTotalArmor());
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return simulateFight(player, boss) ? 0 : equipment.getTotalCost();
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}
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}

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