2018 Day09 Complete

2018/day09/day09.go

@@ -0,0 +1,143 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+)
+
+var playerCount, marbleCount int
+var game *Game
+
+func main() {
+	if len(os.Args) < 3 {
+		fmt.Println("Usage: day09 <# players> <# marbles>")
+		os.Exit(1)
+	}
+	playerCount, marbleCount = Atoi(os.Args[1]), Atoi(os.Args[2])
+	part1()
+}
+
+func part1() {
+	g := NewGame(playerCount, marbleCount)
+	for i := 1; i <= marbleCount; i++ {
+		if i%23 == 0 {
+			g.score(i)
+		} else {
+			g.insertMarble(&Marble{value: i})
+		}
+		g.nextPlayer()
+	}
+	fmt.Println("* Winner *")
+	g.printWinner()
+}
+
+type Game struct {
+	playerCount, marbleCount int
+	currentPlayer            int
+	scores                   map[int]int
+
+	currentMarble *Marble
+}
+
+func NewGame(players, marbles int) *Game {
+	startMarble := &Marble{
+		value: 0,
+	}
+	startMarble.clockwise = startMarble
+	startMarble.widdershins = startMarble
+	return &Game{
+		playerCount:   players,
+		marbleCount:   marbles,
+		currentPlayer: 1,
+		scores:        make(map[int]int),
+		currentMarble: startMarble,
+	}
+}
+
+func (g *Game) insertMarble(m *Marble) {
+	m.clockwise = g.currentMarble.clockwise.clockwise
+	m.widdershins = g.currentMarble.clockwise
+	g.currentMarble.clockwise.clockwise.widdershins = m
+	g.currentMarble.clockwise.clockwise = m
+	g.currentMarble = m
+}
+
+func (g *Game) score(val int) {
+	g.scores[g.currentPlayer] += val
+	for i := 0; i < 6; i++ {
+		g.currentMarble = g.currentMarble.widdershins
+	}
+	// Remove g.currentMarble.widdershins
+	// adding it's value to the current player's score
+	rem := g.currentMarble.widdershins
+	g.currentMarble.widdershins = rem.widdershins
+	g.currentMarble.widdershins.clockwise = g.currentMarble
+	g.scores[g.currentPlayer] += rem.value
+}
+
+func (g *Game) nextPlayer() {
+	if g.currentPlayer == g.playerCount {
+		g.currentPlayer = 1
+	} else {
+		g.currentPlayer++
+	}
+}
+
+func (g *Game) printState() {
+	fmt.Printf("[%d] ", g.currentPlayer)
+	p := *g.currentMarble
+	for p.value != 0 {
+		// Find the '0' marble
+		p = *p.clockwise
+	}
+	if p.value == g.currentMarble.value {
+		fmt.Printf("(%d)", p.value)
+	} else {
+		fmt.Printf(" %d ", p.value)
+	}
+	p = *p.clockwise
+	for p.value != 0 {
+		if p.value == g.currentMarble.value {
+			fmt.Printf("(%d)", p.value)
+		} else {
+			fmt.Printf(" %d ", p.value)
+		}
+		p = *p.clockwise
+	}
+	fmt.Println("")
+}
+
+func (g *Game) printScores() {
+	for i := 1; i <= g.playerCount; i++ {
+		fmt.Println(i, ":", g.scores[i])
+	}
+}
+
+func (g *Game) printWinner() {
+	var top int
+	var winner int
+	for k, v := range g.scores {
+		if v > top {
+			top = v
+			winner = k
+		}
+	}
+	fmt.Println(winner, ":", top)
+}
+
+type Marble struct {
+	value       int
+	clockwise   *Marble
+	widdershins *Marble
+}
+
+func Atoi(i string) int {
+	var ret int
+	var err error
+	if ret, err = strconv.Atoi(i); err != nil {
+		log.Fatal("Invalid Atoi")
+	}
+	return ret
+}