advent-of-code-2022/day16/common/volcano.go

package common

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


type Valve struct {
  name string
  rate int
  tunnels map[*Valve]struct{}
  distances map[*Valve]int
}

func (valve *Valve) GetBestPathFromValveWithHelper(otherValves map[*Valve]int, minutesLeft int, helperValve *Valve, helperMinutesLeft int) int {
  max := 0
  current := 0

  if minutesLeft > 0 {
    current += (minutesLeft - 1) * valve.rate
  }
  if helperMinutesLeft > 0 {
    current += (helperMinutesLeft - 1) * helperValve.rate
  }

  if minutesLeft > 0 || helperMinutesLeft > 0 {
    for relevantValve := range(otherValves) {
      done := false
      if minutesLeft <= 0 {
        done = true
      }
      if minutesLeft - valve.distances[relevantValve] <= 0 {
        relevantValve = valve
        minutesLeft = 0
      }

      for relevantValve2 := range(otherValves) {
        helperDone := false
        if helperMinutesLeft <= 0 {
          helperDone = true
        }
        if helperMinutesLeft - helperValve.distances[relevantValve2] <= 0 {
          relevantValve2 = helperValve
          helperMinutesLeft = 0
        }

        if relevantValve != relevantValve2 {
          currentRelevantValves := make(map[*Valve]int)
          for relevantValve3, relevantValveRate3 := range(otherValves) {
            if relevantValve != relevantValve3 && relevantValve2 != relevantValve3 {
              currentRelevantValves[relevantValve3] = relevantValveRate3
            }
          }
          currentMax := relevantValve.GetBestPathFromValveWithHelper(currentRelevantValves, minutesLeft - 1 - valve.distances[relevantValve],
                                                                     relevantValve2, helperMinutesLeft - 1 - helperValve.distances[relevantValve2])
          if currentMax > max {
            max = currentMax
          }
        } else if len(otherValves) == 1 {
          currentMax := relevantValve.GetBestPathFromValveWithHelper(make(map[*Valve]int), minutesLeft - 1 - valve.distances[relevantValve],
                                                                     helperValve, 0)
          if currentMax > max {
            max = currentMax
          }
          currentMax = valve.GetBestPathFromValveWithHelper(make(map[*Valve]int), 0,
                                                            relevantValve2, helperMinutesLeft - 1 - helperValve.distances[relevantValve2])
          if currentMax > max {
            max = currentMax
          }
        }

        if helperDone {
          break
        }
      }

      if done {
        break
      }
    }
  }

  return max + current
}

func (valve *Valve) GetBestPathFromValve(otherValves map[*Valve]int, minutesLeft int) int {
  if minutesLeft <= 0 {
    return 0
  }

  current := (minutesLeft - 1) * valve.rate
  max := 0

  for relevantValve := range(otherValves) {
    currentRelevantValves := make(map[*Valve]int)
    for relevantValve2, relevantValveRate2 := range(otherValves) {
      if relevantValve != relevantValve2 {
        currentRelevantValves[relevantValve2] = relevantValveRate2
      }
    }
    currentMax := relevantValve.GetBestPathFromValve(currentRelevantValves, minutesLeft - 1 - valve.distances[relevantValve])
    if currentMax > max {
      max = currentMax
    }
  }

  return max + current
}


type Volcano struct {
  valves []*Valve
  current *Valve
  rate int
  pressure int
  minutesLeft int
}

func (volcano *Volcano) GetBestPath(minutesLeft int, helper bool) int {
  relevantValves := make(map[*Valve]int)
  for valve := range volcano.valves {
    if volcano.valves[valve].rate > 0 {
      relevantValves[volcano.valves[valve]] = volcano.valves[valve].rate
    }
  }

  if helper {
    return volcano.current.GetBestPathFromValveWithHelper(relevantValves, minutesLeft + 1, volcano.current, minutesLeft + 1)
  } else {
    return volcano.current.GetBestPathFromValve(relevantValves, minutesLeft + 1)
  }
}

func (volcano *Volcano) ComputeDistances() bool {
  changesFound := false
  for valveSource := range volcano.valves {
    for valveTarget1 := range volcano.valves[valveSource].distances {
      for valveTarget2 := range volcano.valves[valveSource].distances {
        d, ok := valveTarget1.distances[valveTarget2]
        newDistance := volcano.valves[valveSource].distances[valveTarget1] +
                       volcano.valves[valveSource].distances[valveTarget2]
        if !ok || newDistance < d {
          valveTarget1.distances[valveTarget2] = newDistance
          valveTarget2.distances[valveTarget1] = newDistance
          changesFound = true
        }
      }
    }
  }
  return changesFound
}

func (volcano *Volcano) Print() {
  for i := range(volcano.valves) {
    fmt.Print(volcano.valves[i].name)
    fmt.Print(": ")
    fmt.Println(volcano.valves[i].rate)
    for valve, d := range(volcano.valves[i].distances) {
      fmt.Print("  ")
      fmt.Print(valve.name)
      fmt.Print(": ")
      fmt.Println(d)
    }
  }
}


func Parse(scanner bufio.Scanner) Volcano {
  volcano := Volcano{}
  volcano.valves = []*Valve{}
  destinations := make(map[string][]string)

  for scanner.Scan() {
    line := scanner.Text()
    splittedLine := strings.Split(line, " ")
    name := splittedLine[1]
    rate, _ := strconv.Atoi(splittedLine[4][5:len(splittedLine[4])-1])
    destinations[name] = []string{}
    for i := 9; i < len(splittedLine); i++ {
      destinations[name] = append(destinations[name], splittedLine[i][0:2])
    }
    volcano.valves = append(volcano.valves, &Valve{name, rate, map[*Valve]struct{}{}, make(map[*Valve]int)})
  }

  for valveName, currDestinations := range(destinations) {
    var valveSource *Valve
    for i := range volcano.valves {
      if volcano.valves[i].name == valveName {
        valveSource = volcano.valves[i]
        valveSource.distances[valveSource] = 0
        break
      }
    }
    for _, destination := range currDestinations {
      var valveDestination *Valve
      for i := range volcano.valves {
        if volcano.valves[i].name == destination {
          valveDestination = volcano.valves[i]
        }
      }
      valveSource.tunnels[valveDestination] = struct{}{}
      valveSource.distances[valveDestination] = 1
    }
  }

  for i := range(volcano.valves) {
    if volcano.valves[i].name == "AA" {
      volcano.current = volcano.valves[i]
    }
  }
  volcano.minutesLeft = 30

  for volcano.ComputeDistances() {}

  return volcano
}