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solutions/day19/day19.go

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+package day19
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+)
+
+type Blueprint struct {
+	blueprintNumber   int
+	oreRobotOreCost   int
+	clayRobotOreCost  int
+	obsRobotOreCost   int
+	obsRobotClayCost  int
+	geodeRobotOreCost int
+	geodeRobotObsCost int
+}
+
+type State struct {
+	minute   int
+	ore      int
+	clay     int
+	obsidian int
+	geodes   int
+
+	oreRobots      int
+	clayRobots     int
+	obsidianRobots int
+	geodeRobots    int
+}
+
+var initialState State = State{0, 0, 0, 0, 0, 1, 0, 0, 0}
+
+func copyState(state State) State {
+	return State{
+		state.minute,
+		state.ore,
+		state.clay,
+		state.obsidian,
+		state.geodes,
+		state.oreRobots,
+		state.clayRobots,
+		state.obsidianRobots,
+		state.geodeRobots,
+	}
+}
+
+func nextStates(current State, minutes int, blueprint Blueprint) []State {
+	if current.minute == minutes {
+		return []State{}
+	}
+
+	buyNothing := State{
+		current.minute + 1,
+		current.ore + current.oreRobots,
+		current.clay + current.clayRobots,
+		current.obsidian + current.obsidianRobots,
+		current.geodes + current.geodeRobots,
+		current.oreRobots,
+		current.clayRobots,
+		current.obsidianRobots,
+		current.geodeRobots,
+	}
+
+	retval := []State{buyNothing}
+
+	if current.ore >= blueprint.oreRobotOreCost {
+		buyOre := copyState(buyNothing)
+		buyOre.ore -= blueprint.oreRobotOreCost
+		buyOre.oreRobots += 1
+		retval = append(retval, buyOre)
+	}
+
+	if current.ore >= blueprint.clayRobotOreCost {
+		buyClay := copyState(buyNothing)
+		buyClay.ore -= blueprint.clayRobotOreCost
+		buyClay.clayRobots += 1
+		retval = append(retval, buyClay)
+	}
+
+	if current.ore >= blueprint.obsRobotOreCost && current.clay >= blueprint.obsRobotClayCost {
+		buyObsidian := copyState(buyNothing)
+		buyObsidian.ore -= blueprint.obsRobotOreCost
+		buyObsidian.clay -= blueprint.obsRobotClayCost
+		buyObsidian.obsidianRobots += 1
+		retval = append(retval, buyObsidian)
+	}
+
+	if current.ore >= blueprint.geodeRobotOreCost && current.obsidian >= blueprint.geodeRobotObsCost {
+		buyGeode := copyState(buyNothing)
+		buyGeode.ore -= blueprint.geodeRobotOreCost
+		buyGeode.obsidian -= blueprint.geodeRobotObsCost
+		buyGeode.geodeRobots += 1
+		retval = append(retval, buyGeode)
+	}
+
+	return retval
+}
+
+func runSimulation(blueprint Blueprint, minutes int) int {
+	visited := map[State]bool{}
+	queue := []State{initialState}
+	bestResult := 0
+
+	for len(queue) > 0 {
+		nextState := queue[len(queue)-1]
+		queue = queue[0 : len(queue)-1]
+
+		_, alreadyDone := visited[nextState]
+		if alreadyDone {
+			continue
+		}
+		visited[nextState] = true
+
+		minutesLeft := minutes - nextState.minute
+		bestPossibleFuture := nextState.geodes + (minutesLeft*(2*nextState.geodeRobots+(minutesLeft-1)))/2
+		if bestPossibleFuture < bestResult {
+			continue
+		}
+
+		newStates := nextStates(nextState, minutes, blueprint)
+		if len(newStates) == 0 {
+			if nextState.geodes > bestResult {
+				bestResult = nextState.geodes
+			}
+		}
+		queue = append(queue, newStates...)
+	}
+
+	return bestResult
+}
+
+func Run(filename string) {
+	file, err := os.Open(filename)
+	if err != nil {
+		fmt.Println("Error opening file:", err)
+		return
+	}
+
+	scanner := bufio.NewScanner(file)
+	scanner.Split(bufio.ScanLines)
+	blueprints := []Blueprint{}
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		var blueprintNumber, oreRobotOre, clayRobotOre, obsRobotOre, obsRobotClay, geodeRobotOre, geodeRobotObs int
+		fmt.Sscanf(line, "Blueprint %d: Each ore robot costs %d ore. Each clay robot costs %d ore. Each obsidian robot costs %d ore and %d clay. Each geode robot costs %d ore and %d obsidian.", &blueprintNumber, &oreRobotOre, &clayRobotOre, &obsRobotOre, &obsRobotClay, &geodeRobotOre, &geodeRobotObs)
+		blueprints = append(blueprints, Blueprint{blueprintNumber, oreRobotOre, clayRobotOre, obsRobotOre, obsRobotClay, geodeRobotOre, geodeRobotObs})
+	}
+	file.Close()
+
+	fmt.Println("Blueprints", blueprints)
+	totalQualityLevel := 0
+	for _, blueprint := range blueprints {
+		geodesHarvested := runSimulation(blueprint, 24)
+		fmt.Println("Found", geodesHarvested, "geodes for blueprint", blueprint.blueprintNumber)
+		totalQualityLevel += geodesHarvested * blueprint.blueprintNumber
+	}
+	fmt.Println("Total quality level of all blueprints at 24 minutes is", totalQualityLevel)
+
+	multipliedGeodes := 1
+	if len(blueprints) > 3 {
+		blueprints = blueprints[0:3]
+	}
+	for _, blueprint := range blueprints {
+		geodesHarvested := runSimulation(blueprint, 32)
+		fmt.Println("Found", geodesHarvested, "geodes for blueprint", blueprint.blueprintNumber)
+		multipliedGeodes *= geodesHarvested
+	}
+	fmt.Println("Multiplied number of geodes of first three blueprints at 32 minutes is", multipliedGeodes)
+}