advent-of-code-2022/day21/common/monkey2.go

package common

import (
	"bufio"
	"strconv"
	"strings"
)


type Monkey interface {
  Apply() int
  Invert(int) int
  IsHuman() bool
}


type Human struct {
  name string
  number int
}

func (monkey *Human) Apply() int {
  return monkey.number
}

func (monkey *Human) Invert(total int) int {
  return total
}

func (monkey *Human) IsHuman() bool {
  return true
}


type NumberMonkey struct {
  name string
  number int
}

func (monkey *NumberMonkey) Apply() int {
  return monkey.number
}

func (monkey *NumberMonkey) Invert(total int) int {
  return total - monkey.number
}

func (monkey *NumberMonkey) IsHuman() bool {
  return false
}


type PlusMonkey struct {
  name string
  operand1 Monkey
  operand2 Monkey
}

func (monkey *PlusMonkey) Apply() int {
  return monkey.operand1.Apply() + monkey.operand2.Apply()
}

func (monkey *PlusMonkey) Invert(total int) int {
  if monkey.operand1.IsHuman() {
    return monkey.operand1.Invert(total - monkey.operand2.Apply())
  } else {
    return monkey.operand2.Invert(total - monkey.operand1.Apply())
  }
}

func (monkey *PlusMonkey) IsHuman() bool {
  return monkey.operand1.IsHuman() || monkey.operand2.IsHuman()
}


type MinusMonkey struct {
  name string
  operand1 Monkey
  operand2 Monkey
}

func (monkey *MinusMonkey) Apply() int {
  return monkey.operand1.Apply() - monkey.operand2.Apply()
}

func (monkey *MinusMonkey) Invert(total int) int {
  if monkey.operand1.IsHuman() {
    return monkey.operand1.Invert(total + monkey.operand2.Apply())
  } else {
    return monkey.operand2.Invert(monkey.operand1.Apply() - total)
  }
}

func (monkey *MinusMonkey) IsHuman() bool {
  return monkey.operand1.IsHuman() || monkey.operand2.IsHuman()
}


type TimesMonkey struct {
  name string
  operand1 Monkey
  operand2 Monkey
}

func (monkey *TimesMonkey) Apply() int {
  return monkey.operand1.Apply() * monkey.operand2.Apply()
}

func (monkey *TimesMonkey) Invert(total int) int {
  if monkey.operand1.IsHuman() {
    return monkey.operand1.Invert(total / monkey.operand2.Apply())
  } else {
    return monkey.operand2.Invert(total / monkey.operand1.Apply())
  }
}

func (monkey *TimesMonkey) IsHuman() bool {
  return monkey.operand1.IsHuman() || monkey.operand2.IsHuman()
}


type DivisionMonkey struct {
  name string
  operand1 Monkey
  operand2 Monkey
}

func (monkey *DivisionMonkey) Apply() int {
  return monkey.operand1.Apply() / monkey.operand2.Apply()
}

func (monkey *DivisionMonkey) Invert(total int) int {
  if monkey.operand1.IsHuman() {
    return monkey.operand1.Invert(total * monkey.operand2.Apply())
  } else {
    return monkey.operand2.Invert(monkey.operand1.Apply() / total)
  }
}

func (monkey *DivisionMonkey) IsHuman() bool {
  return monkey.operand1.IsHuman() || monkey.operand2.IsHuman()
}


type EqualityMonkey struct {
  name string
  operand1 Monkey
  operand2 Monkey
}

func (monkey *EqualityMonkey) Apply() int {
  if monkey.operand1.Apply() == monkey.operand2.Apply() {
    return 1
  } else {
    return 0
  }
}

func (monkey *EqualityMonkey) Invert(total int) int {
  if monkey.operand1.IsHuman() {
    return monkey.operand1.Invert(monkey.operand2.Apply() - total)
  } else {
    return monkey.operand2.Invert(monkey.operand1.Apply() - total)
  }
}

func (monkey *EqualityMonkey) IsHuman() bool {
  return monkey.operand1.IsHuman() || monkey.operand2.IsHuman()
}


type StringCouple struct {
  left string
  right string
}


type UnresolvedMonkey struct {
  name string
  symbol string
}


func Parse(scanner bufio.Scanner, rootIsEquality bool) Monkey {
  unresolvedMonkeys := make(map[StringCouple]UnresolvedMonkey)
  resolvedMonkeys := make(map[string]Monkey)

  for scanner.Scan() {
    line := scanner.Text()
    splittedLine := strings.Split(line, " ")
    if len(splittedLine) == 2 {
      number, _ := strconv.Atoi(splittedLine[1])
      if splittedLine[0][:4] == "humn" {
        resolvedMonkeys[splittedLine[0][:4]] = &Human{splittedLine[0][:4], number}
      } else {
        resolvedMonkeys[splittedLine[0][:4]] = &NumberMonkey{splittedLine[0][:4], number}
      }
    } else {
      unresolvedMonkeys[StringCouple{splittedLine[1], splittedLine[3]}] = UnresolvedMonkey{splittedLine[0][:4], splittedLine[2]}
    }
  }

  for len(unresolvedMonkeys) > 0 {
    for monkeyCouple := range(unresolvedMonkeys) {
      monkey1, ok1 := resolvedMonkeys[monkeyCouple.left]
      monkey2, ok2 := resolvedMonkeys[monkeyCouple.right]
      if ok1 && ok2 {
        if rootIsEquality && unresolvedMonkeys[monkeyCouple].name == "root" {
          resolvedMonkeys[unresolvedMonkeys[monkeyCouple].name] = &EqualityMonkey{unresolvedMonkeys[monkeyCouple].name, monkey1, monkey2}
        } else {
          switch unresolvedMonkeys[monkeyCouple].symbol {
            case "+":
              resolvedMonkeys[unresolvedMonkeys[monkeyCouple].name] = &PlusMonkey{unresolvedMonkeys[monkeyCouple].name, monkey1, monkey2}
            case "-":
              resolvedMonkeys[unresolvedMonkeys[monkeyCouple].name] = &MinusMonkey{unresolvedMonkeys[monkeyCouple].name, monkey1, monkey2}
            case "*":
              resolvedMonkeys[unresolvedMonkeys[monkeyCouple].name] = &TimesMonkey{unresolvedMonkeys[monkeyCouple].name, monkey1, monkey2}
            case "/":
              resolvedMonkeys[unresolvedMonkeys[monkeyCouple].name] = &DivisionMonkey{unresolvedMonkeys[monkeyCouple].name, monkey1, monkey2}
          }
        }
        delete(unresolvedMonkeys, monkeyCouple)
      }
    }
  }

  return resolvedMonkeys["root"]
}