Day 11 solution

days/11.go

@@ -0,0 +1,118 @@
+package days
+
+import (
+	"fmt"
+	"strings"
+
+	u "parnic.com/aoc2019/utilities"
+)
+
+type Day11 struct {
+	program u.IntcodeProgram
+	painted map[u.Pair[int, int]]int
+}
+
+func (d *Day11) Parse() {
+	d.program = u.LoadIntcodeProgram("11p")
+}
+
+func (d Day11) Num() int {
+	return 11
+}
+
+func (d *Day11) paintHull() (int, u.Pair[int, int], u.Pair[int, int]) {
+	pos := u.Pair[int, int]{First: 0, Second: 0}
+	facing := 0
+
+	min := pos
+	max := pos
+
+	outputState := 0
+	numPainted := 1
+	d.program.RunIn(func(inputStep int) int64 {
+		return int64(d.painted[pos])
+	}, func(val int64, state u.IntcodeProgramState) {
+		if outputState == 0 {
+			outputState++
+			color := int(val)
+			if _, exists := d.painted[pos]; !exists {
+				numPainted++
+			}
+			d.painted[pos] = color
+		} else {
+			outputState = 0
+			direction := val
+
+			if direction == 0 {
+				facing--
+				if facing == -1 {
+					facing = 3
+				}
+			} else {
+				facing++
+				if facing == 4 {
+					facing = 0
+				}
+			}
+
+			switch facing {
+			case 0:
+				pos.First--
+				if pos.First < min.First {
+					min.First = pos.First
+				}
+			case 1:
+				pos.Second++
+				if pos.Second > max.Second {
+					max.Second = pos.Second
+				}
+			case 2:
+				pos.First++
+				if pos.First > max.First {
+					max.First = pos.First
+				}
+			case 3:
+				pos.Second--
+				if pos.Second < min.Second {
+					min.Second = pos.Second
+				}
+			}
+		}
+	})
+
+	return numPainted, min, max
+}
+
+func (d *Day11) Part1() string {
+	d.painted = map[u.Pair[int, int]]int{
+		{First: 0, Second: 0}: 0,
+	}
+	numPainted, _, _ := d.paintHull()
+
+	return fmt.Sprintf("Unique panels painted: %s%d%s", u.TextBold, numPainted, u.TextReset)
+}
+
+func (d *Day11) Part2() string {
+	d.painted = map[u.Pair[int, int]]int{
+		{First: 0, Second: 0}: 1,
+	}
+	_, min, max := d.paintHull()
+
+	outStr := strings.Builder{}
+	outStr.WriteString("Registration identifier:\n")
+	outStr.WriteString(u.TextBold)
+	for x := min.First; x <= max.First; x++ {
+		for y := min.Second; y <= max.Second; y++ {
+			val, exists := d.painted[u.Pair[int, int]{First: x, Second: y}]
+			if exists && val == 1 {
+				outStr.WriteRune('█')
+			} else {
+				outStr.WriteRune(' ')
+			}
+		}
+		outStr.WriteRune('\n')
+	}
+	outStr.WriteString(u.TextReset)
+
+	return outStr.String()
+}