83 lines
3.1 KiB
C#
83 lines
3.1 KiB
C#
namespace AOC2015;
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/// <summary>
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/// Day 21: <a href="https://adventofcode.com/2015/day/21"/>
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/// </summary>
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public sealed class Day21() : Day(2015, 21, "RPG Simulator 20XX")
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{
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private const int PlayerHp = 100;
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private IEnumerable<Combination>? _combinations;
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private Dictionary<string, int>? _boss;
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private record Combination(Item Weapon, Item Armor, Item Ring1, Item Ring2)
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{
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public int TotalDamage => Weapon.Damage + Ring1.Damage + Ring2.Damage;
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public int TotalArmor => Armor.Armor + Ring1.Armor + Ring2.Armor;
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public int TotalCost => Weapon.Cost + Armor.Cost + Ring1.Cost + Ring2.Cost;
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}
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private record Item(string Name, int Cost = 0, int Damage = 0, int Armor = 0);
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public override void ProcessInput()
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{
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_boss = Input.ToDictionary(k => k.Split(": ")[0], v => int.Parse(v.Split(": ")[1]));
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var weapons = new Item[]
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{
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new(Name: "Dagger", Cost: 8, Damage: 4),
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new(Name: "Shortsword", Cost: 10, Damage: 5),
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new(Name: "Warhammer", Cost: 25, Damage: 6),
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new(Name: "Longsword", Cost: 40, Damage: 7),
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new(Name: "Greataxe", Cost: 74, Damage: 8)
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};
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var armor = new Item[]
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{
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new(Name: "No armor", Cost: 0, Armor: 0),
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new(Name: "Leather", Cost: 13, Armor: 1),
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new(Name: "Chainmail", Cost: 31, Armor: 2),
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new(Name: "Splintmail", Cost: 53, Armor: 3),
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new(Name: "Bandedmail", Cost: 75, Armor: 4),
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new(Name: "Platemail", Cost: 102, Armor: 5)
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};
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var rings = new Item[]
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{
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new(Name: "No ring", Cost: 0, Damage: 0, Armor: 0),
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new(Name: "Damage +1", Cost: 25, Damage: 1, Armor: 0),
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new(Name: "Damage +2", Cost: 50, Damage: 2, Armor: 0),
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new(Name: "Damage +3", Cost: 100, Damage: 3, Armor: 0),
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new(Name: "Defense +1", Cost: 20, Damage: 0, Armor: 1),
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new(Name: "Defense +2", Cost: 40, Damage: 0, Armor: 2),
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new(Name: "Defense +3", Cost: 80, Damage: 0, Armor: 3)
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};
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_combinations =
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from w in weapons
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from a in armor
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from ring1 in rings
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from ring2 in rings
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where ring1.Cost == 0 || ring1.Cost != ring2.Cost
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select new Combination(w, a, ring1, ring2);
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}
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private bool StillAlive(Combination combination)
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{
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var myDamage = Math.Max(combination.TotalDamage - _boss!["Armor"], 1);
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var bossDamagePerTurn = Math.Max(_boss["Damage"] - combination.TotalArmor, 1);
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var turnsToLose = PlayerHp / bossDamagePerTurn;
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if (PlayerHp % bossDamagePerTurn > 0) turnsToLose++;
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var turnsToKillBoss = _boss["Hit Points"] / myDamage;
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if (_boss["Hit Points"] % myDamage > 0) turnsToKillBoss++;
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return turnsToLose >= turnsToKillBoss;
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}
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public override object Part1() =>
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_combinations!.Where(StillAlive).Min(c => c.TotalCost);
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public override object Part2() =>
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_combinations!.Where(c => !StillAlive(c)).Max(c => c.TotalCost);
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} |