feat: solve 15 1

15.go

@@ -0,0 +1,137 @@
+package main
+
+import (
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+type AOC202215MapPoint int
+
+const (
+	MPBeacon AOC202215MapPoint = iota
+	MPSensor
+	MPNoBeacon
+)
+
+type AOC202215SensorBeacon struct {
+	Sensor   []int
+	Beacon   []int
+	Distance int
+}
+
+type AOC202215Map struct {
+	SensorBeacons []*AOC202215SensorBeacon
+	Map           map[int]map[int]AOC202215MapPoint
+}
+
+func (m *AOC202215Map) SetPoint(x, y int, pt AOC202215MapPoint) {
+	if m.Map == nil {
+		m.Map = make(map[int]map[int]AOC202215MapPoint)
+	}
+	if _, ok := m.Map[y]; !ok {
+		m.Map[y] = make(map[int]AOC202215MapPoint)
+	}
+
+	m.Map[y][x] = pt
+}
+
+func (m *AOC202215Map) GetRow(y int) map[int]AOC202215MapPoint {
+	row, ok := m.Map[y]
+	if !ok {
+		return nil
+	}
+
+	return row
+}
+
+func (m *AOC202215Map) PopulateMap() {
+	for _, sb := range m.SensorBeacons {
+		for y := sb.Sensor[1] - sb.Distance; y <= sb.Sensor[1]+sb.Distance; y++ {
+			xDelta := sb.Distance - absInt(sb.Sensor[1]-y)
+			for x := sb.Sensor[0] - xDelta; x <= sb.Sensor[0]+xDelta; x++ {
+				m.SetPoint(x, y, MPNoBeacon)
+			}
+		}
+		m.SetPoint(sb.Beacon[0], sb.Beacon[1], MPBeacon)
+		m.SetPoint(sb.Sensor[0], sb.Sensor[1], MPSensor)
+	}
+}
+
+func (m *AOC202215Map) PopulateMapROI(row int) {
+	for _, sb := range m.SensorBeacons {
+		yMin := sb.Sensor[1] - sb.Distance
+		yMax := sb.Sensor[1] + sb.Distance
+		if yMin > row || yMax < row {
+			continue
+		}
+
+		xDelta := sb.Distance - absInt(sb.Sensor[1]-row)
+		for x := sb.Sensor[0] - xDelta; x <= sb.Sensor[0]+xDelta; x++ {
+			m.SetPoint(x, row, MPNoBeacon)
+		}
+
+		m.SetPoint(sb.Beacon[0], sb.Beacon[1], MPBeacon)
+		m.SetPoint(sb.Sensor[0], sb.Sensor[1], MPSensor)
+	}
+}
+
+func (m *AOC202215Map) ParseInput(input string) error {
+	m.SensorBeacons = []*AOC202215SensorBeacon{}
+	re := regexp.MustCompile(`Sensor at x=(-?\d+), y=(-?\d+): closest beacon is at x=(-?\d+), y=(-?\d+)`)
+	for _, line := range strings.Split(input, "\n") {
+		parts := re.FindStringSubmatch(line)
+		if len(parts) != 5 {
+			return fmt.Errorf("can't parse line %s", line)
+		}
+		intParts := []int{}
+		for _, part := range parts[1:] {
+			intPart, err := strconv.Atoi(part)
+			if err != nil {
+				return fmt.Errorf("can't convert %s to int: %v", part, err)
+			}
+			intParts = append(intParts, intPart)
+		}
+
+		sb := &AOC202215SensorBeacon{
+			Sensor:   intParts[:2],
+			Beacon:   intParts[2:],
+			Distance: absInt(intParts[0]-intParts[2]) + absInt(intParts[1]-intParts[3]),
+		}
+		m.SensorBeacons = append(m.SensorBeacons, sb)
+	}
+
+	return nil
+}
+
+func AOC2022151Helper(input string, row int) (int, error) {
+	sbMap := &AOC202215Map{}
+	err := sbMap.ParseInput(input)
+	if err != nil {
+		return 0, fmt.Errorf("can't parse input: %v", err)
+	}
+	sbMap.PopulateMapROI(row)
+
+	count := 0
+	mapRow := sbMap.GetRow(row)
+	if mapRow == nil {
+		return 0, fmt.Errorf("row %d is empty", row)
+	}
+	for k := range mapRow {
+		if mapRow[k] != MPBeacon {
+			count += 1
+		}
+	}
+
+	return count, nil
+}
+
+func AOC2022151(input string) (string, error) {
+	res, err := AOC2022151Helper(input, 2000000)
+	if err != nil {
+		return "", err
+	}
+
+	return fmt.Sprintf("%d", res), nil
+}

15_test.go

@@ -0,0 +1,35 @@
+package main
+
+import "testing"
+
+func TestAOC2022151(t *testing.T) {
+	test := struct {
+		input  string
+		result int
+	}{
+		input: `Sensor at x=2, y=18: closest beacon is at x=-2, y=15
+Sensor at x=9, y=16: closest beacon is at x=10, y=16
+Sensor at x=13, y=2: closest beacon is at x=15, y=3
+Sensor at x=12, y=14: closest beacon is at x=10, y=16
+Sensor at x=10, y=20: closest beacon is at x=10, y=16
+Sensor at x=14, y=17: closest beacon is at x=10, y=16
+Sensor at x=8, y=7: closest beacon is at x=2, y=10
+Sensor at x=2, y=0: closest beacon is at x=2, y=10
+Sensor at x=0, y=11: closest beacon is at x=2, y=10
+Sensor at x=20, y=14: closest beacon is at x=25, y=17
+Sensor at x=17, y=20: closest beacon is at x=21, y=22
+Sensor at x=16, y=7: closest beacon is at x=15, y=3
+Sensor at x=14, y=3: closest beacon is at x=15, y=3
+Sensor at x=20, y=1: closest beacon is at x=15, y=3`,
+		result: 26,
+	}
+
+	got, err := AOC2022151Helper(test.input, 10)
+	if err != nil {
+		t.Fatalf("AOC2022151Helper() err: %v", err)
+	}
+
+	if got != test.result {
+		t.Errorf("AOC2022151Helper() missmatch:\nwant: %d\ngot:  %d", test.result, got)
+	}
+}