adventofcode/2022/day15/main.go

package main

import (
	"fmt"
	"math"
	"os"
	"strings"
	"time"

	h "git.bullercodeworks.com/brian/adventofcode/helpers"
)

var part = -1
var testRow = 2000000
var watch bool
var watchRows = 1

func main() {
	inp := h.StdinToStringSlice()
	if len(os.Args) > 1 {
		for _, arg := range os.Args[1:] {
			if strings.HasPrefix(arg, "--part") || strings.HasPrefix(arg, "-p") {
				if strings.Contains(arg, "=") {
					pts := strings.Split(arg, "=")
					part = h.Atoi(pts[1])
				}
			} else if strings.HasPrefix(arg, "--row") || strings.HasPrefix(arg, "-r") {
				if strings.Contains(arg, "=") {
					pts := strings.Split(arg, "=")
					testRow = h.Atoi(pts[1])
				}
			} else if strings.HasPrefix(arg, "--watch") || strings.HasPrefix(arg, "-w") {
				watch = true
				if strings.Contains(arg, "=") {
					pts := strings.Split(arg, "=")
					if pts[1] == "full" {
						watchRows = -1
					} else {
						watchRows = h.Atoi(pts[1])
					}
				}
			}
		}
	}

	if part == 1 || part == -1 {
		part1(inp)
	}
	if part == 2 || part == -1 {
		part2(inp)
	}
}

func part1(inp []string) {
	min_x, max_x := math.MaxInt, math.MinInt
	var spots [][]int
	for i := range inp {
		s, b := strToCoords(inp[i])
		xs, ys, xb, yb := s.X, s.Y, b.X, b.Y
		dist := s.Distance(b)
		l, r := xs-dist, xs+dist
		min_x = h.Min(min_x, l)
		max_x = h.Max(max_x, r)
		spots = append(spots, []int{xs, ys, xb, yb, dist})
	}
	var nopeCount int
	for x := min_x; x <= max_x; x++ {
		for _, c := range spots {
			if x == c[2] && testRow == c[3] {
				break
			}
			if h.ManhattanDistance(x, testRow, c[0], c[1]) <= c[4] {
				nopeCount++
				break
			}
		}
	}
	fmt.Println("# Part 1")
	fmt.Println(nopeCount)
}

type Sensor struct {
	c h.Coordinate // Sensor Position
	b h.Coordinate // Beacon Position
	d int          // Distance
}

func (s Sensor) isInRange(c h.Coordinate) bool { return s.c.Distance(c) <= s.d }

func (s Sensor) String() string { return s.c.String() }

func part2(inp []string) {
	var sensors []Sensor
	for i := range inp {
		s := Sensor{}
		s.c, s.b = strToCoords(inp[i])
		s.d = s.c.Distance(s.b)
		sensors = append(sensors, s)
	}

	max := testRow * 2
	found := []h.Coordinate{}
	// Check around each sensor, the beacon must be it's distance + 1
	for _, sensor := range sensors {
		d := sensor.d + 1
		testEnds := []h.Coordinate{
			{X: sensor.c.X, Y: sensor.c.Y - d},
			{X: sensor.c.X + d, Y: sensor.c.Y},
			{X: sensor.c.X, Y: sensor.c.Y + d},
			{X: sensor.c.X - d, Y: sensor.c.Y},
		}
		printMap(sensors, max, max, h.Coordinate{X: math.MinInt, Y: math.MinInt})
		var tstX, tstY int
		for i := 0; i < 3; i++ {
			// Test all spots between testEnds[i] & testEnds[i+1]
			for tstX != testEnds[i+1].X && tstY != testEnds[i+1].Y {
				if testEnds[i].X < testEnds[i+1].X {
					tstX++
					if testEnds[i].Y < testEnds[i+1].Y {
						tstY++
					} else {
						tstY--
					}
				} else {
					tstX--
					if testEnds[i].Y < testEnds[i+1].Y {
						tstY++
					} else {
						tstY--
					}
				}
			}
			if tstX <= max && tstY <= max {
				fmt.Print(h.CLEAR_SCREEN)
				printMap(sensors, max, max, h.Coordinate{X: tstX, Y: tstY})
				fmt.Println("Testing", tstX, ",", tstY)
				time.Sleep(time.Second / 10)
				if testSpot(tstX, tstY, sensors) {
					found = append(found, h.Coordinate{X: tstX, Y: tstY})
				}
			}
		}
	}

	fmt.Println("# Part 2")
	fmt.Println(found)
	//fmt.Println((found.X * 4000000) + found.Y)
}

func testSpot(x, y int, sensors []Sensor) bool {
	var wasInRange bool
	for i := range sensors {
		if sensors[i].isInRange(h.Coordinate{X: x, Y: y}) {
			wasInRange = true
			break
		}
	}
	return !wasInRange
}

func printMap(sensors []Sensor, ceilX, ceilY int, tstPos h.Coordinate) {
	minX, maxX, minY, maxY := math.MaxInt, math.MinInt, math.MaxInt, math.MinInt
	for i := range sensors {
		minX = h.Min(sensors[i].b.X, minX)
		maxX = h.Max(sensors[i].b.X, maxX)
		minY = h.Min(sensors[i].b.Y, minY)
		maxY = h.Max(sensors[i].b.Y, maxY)
	}
	for y := minY; y <= maxY; y++ {
		for x := minX; x <= maxX; x++ {
			wrk := h.Coordinate{X: x, Y: y}
			var found bool
			for _, sensor := range sensors {
				if sensor.c.Equals(wrk) {
					fmt.Print("S")
					found = true
					break
				} else if sensor.b.Equals(wrk) {
					fmt.Print("B")
					found = true
					break
				} else if sensor.isInRange(wrk) {
					fmt.Print("#")
					found = true
					break
				}
			}
			if !found {
				if wrk.Equals(tstPos) {
					fmt.Print(h.FILL_CHAR)
				} else {
					fmt.Print(".")
				}
			}
		}
		fmt.Println()
	}
}

func strToCoords(s string) (h.Coordinate, h.Coordinate) {
	var sensor, beacon h.Coordinate
	r := strings.NewReader(s)
	fmt.Fscanf(r, "Sensor at x=%d, y=%d: closest beacon is at x=%d, y=%d", &sensor.X, &sensor.Y, &beacon.X, &beacon.Y)
	return sensor, beacon
}