Started working on day 17

2018/day13/day13.go

@@ -42,8 +42,11 @@ func part1() {
 	}
 }
 
+var ticks int
+
 func part2() {
 	for len(cartMap) > 1 {
+		ticks++
 		sort.Sort(ByPos(carts))
 		for _, c := range carts {
 			if *c != 0 {
@@ -54,6 +57,7 @@ func part2() {
 	for pos := range cartMap {
 		fmt.Printf("🔵: %0.0f,%0.0f\n", real(pos), imag(pos))
 	}
+	fmt.Println("Ticks: ", ticks)
 }
 
 type Cart struct {
@@ -69,7 +73,7 @@ func (c *Cart) tick() bool {
 	delete(cartMap, c.pos)
 	c.pos += c.dir
 	if cart, ok := cartMap[c.pos]; ok {
-		fmt.Printf("❌: %0.0f,%0.0f\n", real(c.pos), imag(c.pos))
+		fmt.Printf("❌: %0.0f,%0.0f (%d ticks)\n", real(c.pos), imag(c.pos), ticks)
 		// Remove the cart we crashed into from the map
 		delete(cartMap, c.pos)
 		// And clear the cart's pos, we can ignore them now

2018/day17/day17.go

@@ -0,0 +1,182 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const (
+	MaxInt      = int(^uint(0) >> 1)
+	MinInt      = -MaxInt - 1
+	ClearScreen = "\033[H\033[2J"
+)
+
+func main() {
+	input := stdinToStringSlice()
+	part1(input)
+	//part2(input)
+}
+
+var scan [1000][1000]byte
+var minX, maxX int = MaxInt, MinInt
+var minY, maxY int = MaxInt, MinInt
+
+func part1(input []string) {
+	for _, v := range input {
+		pts := strings.Split(v, ", ")
+		fst := strings.Split(pts[0], "=")
+		scd := strings.Split(pts[1], "=")
+		scdRange := strings.Split(scd[1], "..")
+		var x, y int
+		if fst[0] == "x" {
+			x = Atoi(fst[1])
+			for y = Atoi(scdRange[0]); y <= Atoi(scdRange[1]); y++ {
+				minmax(x, y)
+				scan[x][y] = '#'
+			}
+		} else if fst[0] == "y" {
+			y = Atoi(fst[1])
+			for x := Atoi(scdRange[0]); x <= Atoi(scdRange[1]); x++ {
+				minmax(x, y)
+				scan[x][y] = '#'
+			}
+		}
+	}
+	printScan()
+	// The water starts at 500, 0
+	fillDown(500, 0)
+}
+
+func part2(input []string) {
+}
+
+// The 'fill<dir>' functions return the x, y that was filled
+// or MinInt, MinInt, if x, y can't be filled
+
+// fillDown will check down, then left, then right
+func fillDown(x, y int) (int, int) {
+	fx, fy := fillSpot(x, y)
+	if !gud(fx, fy) {
+		return fx, fy
+	}
+	// Try to fill the spot below it
+	dx, dy := fillDown(x, y+1)
+	if dx == MinInt && dy == MinInt {
+		// We couldn't go down
+		lx, ly := fillLeft(x-1, y)  // left?
+		rx, ry := fillRight(x+1, y) // right?
+		if !gud(lx, ly) || !gud(rx, ry) {
+			return MinInt, MinInt // Off to infinity
+		}
+		if ly == y && ry == y {
+			scan[lx][y] = '~'
+			scan[rx][y] = '~'
+		}
+	}
+	return dx, dy
+}
+
+func fillLeft(x, y int) (int, int) {
+	fx, fy := fillSpot(x, y)
+	if !gud(fx, fy) {
+		return fx, fy
+	}
+	// This spot can be filled, try to go down
+	rx, ry := fillDown(fx, fy+1)
+	if gud(rx, ry) {
+		return rx, ry
+	}
+	// Couldn't go down, try to go left
+	rx, ry = fillLeft(fx-1, y)
+	if gud(rx, ry) {
+		return rx, ry
+	}
+	return x, y
+}
+
+func fillRight(x, y int) (int, int) {
+	fx, fy := fillSpot(x, y)
+	if !gud(fx, fy) {
+		return fx, fy
+	}
+	// This spot can be filled, try to go down
+	rx, ry := fillDown(fx, fy+1)
+	if gud(rx, ry) {
+		return rx, ry
+	}
+	// Couldn't go down, try to go left
+	rx, ry = fillRight(fx+1, y)
+	if gud(rx, ry) {
+		return rx, ry
+	}
+	return x, y
+}
+
+func fillSpot(x, y int) (int, int) {
+	time.Sleep(time.Millisecond * 250)
+	printScan()
+	if y > maxY || !canFill(x, y) {
+		return MinInt, MinInt
+	}
+	scan[x][y] = '|'
+	return x, y
+}
+
+func gud(x, y int) bool {
+	return x != MinInt && y != MinInt
+}
+
+func printScan() {
+	fmt.Print(ClearScreen)
+	for y := minY; y <= maxY; y++ {
+		for x := minX; x <= maxX; x++ {
+			if scan[x][y] == 0 {
+				fmt.Print(".")
+			} else {
+				fmt.Print(string(scan[x][y]))
+			}
+		}
+		fmt.Println()
+	}
+}
+func canFill(x, y int) bool {
+	return scan[x][y] == 0 || scan[x][y] == '|'
+}
+
+func minmax(x, y int) {
+	if x < minX {
+		minX = x
+	}
+	if x > maxX {
+		maxX = x
+	}
+	if y < minY {
+		minY = y
+	}
+	if y > maxY {
+		maxY = y
+	}
+}
+
+func stdinToStringSlice() []string {
+	var input []string
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		input = append(input, scanner.Text())
+	}
+	return input
+}
+
+func Atoi(i string) int {
+	var ret int
+	var err error
+	if ret, err = strconv.Atoi(i); err != nil {
+		log.Fatal("Invalid Atoi: " + i)
+	}
+	return ret
+}

2018/day17/testinput

@@ -0,0 +1,8 @@
+x=495, y=2..7
+y=7, x=495..501
+x=501, y=3..7
+x=498, y=2..4
+x=506, y=1..2
+x=498, y=10..13
+x=504, y=10..13
+y=13, x=498..504