aoc2015/day21/day.go

package day21

import (
	"math"
	"strconv"
	"strings"
	"tools"
)

var armor = map[string]map[string]int{
	"none": {
		"cost":  0,
		"armor": 0,
	},
	"Leather": {
		"cost":  13,
		"armor": 1,
	},
	"Chainmail": {
		"cost":  31,
		"armor": 2,
	},
	"Splintmail": {
		"cost":  53,
		"armor": 3,
	},
	"Bandedmail": {
		"cost":  75,
		"armor": 4,
	},
	"Platemail": {
		"cost":  102,
		"armor": 5,
	},
}

var weapons = map[string]map[string]int{
	"Dagger": {
		"cost":   8,
		"damage": 4,
	},
	"Shortsword": {
		"cost":   10,
		"damage": 5,
	},
	"Warhammer": {
		"cost":   25,
		"damage": 6,
	},
	"Longsword": {
		"cost":   40,
		"damage": 7,
	},
	"Greataxe": {
		"cost":   74,
		"damage": 8,
	},
}

var rings = map[string]map[string]int{
	"none1": {
		"cost":   0,
		"damage": 0,
		"armor":  0,
	},
	"none2": {
		"cost":   0,
		"damage": 0,
		"armor":  0,
	},
	"Damage +1": {
		"cost":   25,
		"damage": 1,
		"armor":  0,
	},
	"Damage +2": {
		"cost":   50,
		"damage": 2,
		"armor":  0,
	},
	"Damage +3": {
		"cost":   100,
		"damage": 3,
		"armor":  0,
	},
	"Armor +1": {
		"cost":   20,
		"damage": 0,
		"armor":  1,
	},
	"Armor +2": {
		"cost":   40,
		"damage": 0,
		"armor":  2,
	},
	"Armor +3": {
		"cost":   80,
		"damage": 0,
		"armor":  3,
	},
}

func fight(playerHp, playerPower, playerArmor, bossHp, bossPower, bossArmor int) bool {
	playerStrike := float64(tools.Max(1, playerPower-bossArmor))
	bossStrike := float64(tools.Max(1, bossPower-playerArmor))

	return math.Ceil(float64(bossHp)/playerStrike) <= math.Ceil(float64(playerHp)/bossStrike)
}

func Part1(puzzle tools.AoCPuzzle) interface{} {
	input := puzzle.GetInputArray()
	hpLine := strings.Split(input[0], ": ")
	powerLine := strings.Split(input[1], ": ")
	armorLine := strings.Split(input[2], ": ")
	bossHp, _ := strconv.Atoi(hpLine[1])
	bossPower, _ := strconv.Atoi(powerLine[1])
	bossArmor, _ := strconv.Atoi(armorLine[1])

	playerHp := 100
	playerPower := 0
	playerArmor := 0

	goldSpent := 0

	minGold := math.MaxInt32
	for _, weaponStats := range weapons {
		for _, armorStats := range armor {
			goldSpent = weaponStats["cost"] + armorStats["cost"]
			for ring1Name, ring1Stats := range rings {
				for ring2Name, ring2Stats := range rings {
					if ring1Name == ring2Name {
						continue
					}
					goldSpent = weaponStats["cost"] + armorStats["cost"] + ring1Stats["cost"] + ring2Stats["cost"]
					playerPower = weaponStats["damage"] + ring1Stats["damage"] + ring2Stats["damage"]
					playerArmor = armorStats["armor"] + ring1Stats["armor"] + ring2Stats["armor"]

					if fight(playerHp, playerPower, playerArmor, bossHp, bossPower, bossArmor) && goldSpent < minGold {
						minGold = goldSpent
					}
				}
			}
		}
	}

	return minGold
}

func Part2(puzzle tools.AoCPuzzle) interface{} {
	input := puzzle.GetInputArray()
	hpLine := strings.Split(input[0], ": ")
	powerLine := strings.Split(input[1], ": ")
	armorLine := strings.Split(input[2], ": ")
	bossHp, _ := strconv.Atoi(hpLine[1])
	bossPower, _ := strconv.Atoi(powerLine[1])
	bossArmor, _ := strconv.Atoi(armorLine[1])

	playerHp := 100
	playerPower := 0
	playerArmor := 0

	goldSpent := 0

	maxGold := 0
	for _, weaponStats := range weapons {
		for _, armorStats := range armor {
			for ring1Name, ring1Stats := range rings {
				for ring2Name, ring2Stats := range rings {
					if ring1Name == ring2Name {
						continue
					}
					goldSpent = weaponStats["cost"] + armorStats["cost"] + ring1Stats["cost"] + ring2Stats["cost"]
					playerPower = weaponStats["damage"] + ring1Stats["damage"] + ring2Stats["damage"]
					playerArmor = armorStats["armor"] + ring1Stats["armor"] + ring2Stats["armor"]

					if !fight(playerHp, playerPower, playerArmor, bossHp, bossPower, bossArmor) && goldSpent > maxGold {
						maxGold = goldSpent
					}
				}
			}
		}
	}
	return maxGold
}