package main import ( "fmt" "regexp" "sort" "strings" helpers2017 "bitbucket.org/thezeez/advent-of-code-2017/helpers" ) type Battlefield map[int]Army var ( armyName = regexp.MustCompile(`^(.*):$`) groupImmunities = regexp.MustCompile(`immune to (.*?)[;)]`) groupWeaknesses = regexp.MustCompile(`weak to (.*?)[;)]`) groupDescription = regexp.MustCompile(`^(\d+) units each with (\d+) hit points.*with an attack that does (\d+) (\w+) damage at initiative (\d+)$`) ) const ( descriptionCount = iota + 1 descriptionHitPoints descriptionDamage descriptionDamageType descriptionInitiative ) func PrepareForBattle(input []string) (Battlefield, Initiative) { var initiative Initiative battle := make(Battlefield) var currentArmy int for _, line := range input { if armyName.MatchString(line) { if id, ok := StringArmies[armyName.FindStringSubmatch(line)[1]]; ok { currentArmy = id } else { panic(fmt.Errorf("unknown army: %s", armyName.FindStringSubmatch(line)[1])) } } else { if currentArmy <= 0 || currentArmy >= ArmyCount { panic(fmt.Errorf("tried to assign group to invalid army: %d", currentArmy)) } description := groupDescription.FindStringSubmatch(line) if len(description) == 0 { continue } group := &Group{ Units: helpers2017.IntOrPanic(description[descriptionCount]), HitPoints: helpers2017.IntOrPanic(description[descriptionHitPoints]), AttackDamage: helpers2017.IntOrPanic(description[descriptionDamage]), AttackType: description[descriptionDamageType], Initiative: helpers2017.IntOrPanic(description[descriptionInitiative]), } immunities := groupImmunities.FindStringSubmatch(line) if len(immunities) > 0 { group.Immunities = strings.Split(immunities[1], ", ") } weaknesses := groupWeaknesses.FindStringSubmatch(line) if len(weaknesses) > 0 { group.Weaknesses = strings.Split(weaknesses[1], ", ") } battle[currentArmy] = append(battle[currentArmy], group) initiative = append(initiative, group) } } return battle, initiative } func (b Battlefield) FindTargets() { for army, groups := range b { sort.Sort(groups) for _, group := range groups { for enemyArmy, enemyGroups := range b { if army == enemyArmy || group.Units <= 0 { continue } var mostDamage int var targetGroup *Group for _, enemyGroup := range enemyGroups { if enemyGroup.Units <= 0 || enemyGroup.Attacker != nil || group.DamageDealt(enemyGroup) == 0 || group.DamageDealt(enemyGroup) < mostDamage { continue } if group.DamageDealt(enemyGroup) == mostDamage && targetGroup != nil { if enemyGroup.EffectivePower() < targetGroup.EffectivePower() { continue } if enemyGroup.EffectivePower() == targetGroup.EffectivePower() && enemyGroup.Initiative < targetGroup.Initiative { continue } } mostDamage = group.DamageDealt(enemyGroup) targetGroup = enemyGroup } if targetGroup != nil { group.Target = targetGroup targetGroup.Attacker = group } } } } } func (b Battlefield) Clean() { for army := range b { c := b[army][:0] for _, g := range b[army] { if g.Units > 0 { c = append(c, g) } } b[army] = c } } func (b Battlefield) Active() bool { for _, a := range b { if !a.Alive() { return false } } return true } func (b Battlefield) Result() (int, int) { var winner, units int for army, groups := range b { if groups.Alive() { winner = army for _, g := range groups { if g.Units > 0 { units += g.Units } } } } return winner, units } func (b Battlefield) TotalUnits() int { var sum int for _, groups := range b { for _, group := range groups { if group.Units > 0 { sum += group.Units } } } return sum }