~stick/challenges

65a5fc8b33dcd49f5a41581cf7e7e144d0229aff — Stick 1 year, 6 months ago 512a4ee main
AOC2022: day 15
2 files changed, 143 insertions(+), 0 deletions(-)

A advent_of_code/2022/day15.go
A advent_of_code/2022/input15.txt
A advent_of_code/2022/day15.go => advent_of_code/2022/day15.go +114 -0
@@ 0,0 1,114 @@
package main

import (
	"flag"
	"fmt"
	"os"
	"sort"
	"strconv"
	"strings"
)

type mt struct{}

type xy struct {
	x, y int
}

type sensor struct {
	p xy
	d int
}

func abs(x int) int {
	if x < 0 {
		return -x
	}
	return x
}

func main() {
	// Get command-line options
	// debug := flag.Bool("debug", false, "show debugging output")
	flag.Parse()

	// Read the input file
	if len(flag.Args()) < 1 {
		panic("No input file given")
	}
	input, err := os.ReadFile(flag.Args()[0])
	if err != nil {
		panic(err)
	}

	lines := strings.Split(string(input), "\n")
	numLines := len(lines) - 1
	sensors := make([]sensor, 0, numLines)
	beacons := make(map[xy]mt, numLines)
	for _, line := range lines[:numLines] {
		line = strings.ReplaceAll(line, "=", " ")
		line = strings.ReplaceAll(line, ",", "")
		line = strings.ReplaceAll(line, ":", "")
		flds := strings.Fields(line)
		nums := make([]int, 4)
		for i, s := range []string{flds[3], flds[5], flds[11], flds[13]} {
			n, err := strconv.Atoi(s)
			if err != nil {
				panic(err)
			}
			nums[i] = n
		}
		mDist := abs(nums[2]-nums[0]) + abs(nums[3]-nums[1])
		sensors = append(sensors, sensor{xy{nums[0], nums[1]}, mDist})
		beacons[xy{nums[2], nums[3]}] = mt{}
	}

	part1 := 0
	part2 := 0
	for y := 0; y <= 4000000; y++ {
		blocks := make([]xy, 0, numLines)
		for _, s := range sensors {
			dist := -1
			if s.p.y-s.d <= y && y <= s.p.y {
				dist = y - (s.p.y - s.d)
			} else if s.p.y < y && y <= s.p.y+s.d {
				dist = (s.p.y + s.d) - y
			}
			if dist > -1 {
				blocks = append(blocks, xy{s.p.x - dist, s.p.x + dist})
			}
		}
		sort.Slice(blocks, func(i, j int) bool {
			return blocks[i].x < blocks[j].x
		})
		for i := 0; len(blocks) > i+1; {
			if blocks[i+1].x <= blocks[i].y+1 {
				blocks[i+1].x = blocks[i].x
				if blocks[i+1].y < blocks[i].y {
					blocks[i+1].y = blocks[i].y
				}
				blocks = append(blocks[:i], blocks[i+1:]...)
			} else {
				part2 = 4000000*(blocks[0].y+1) + y
				i++
			}
		}

		if y == 2000000 {
			for _, b := range blocks {
				part1 += (b.y - b.x) + 1
			}
			for b := range beacons {
				if b.y == y {
					part1--
				}
			}
		}
		if part1 > 0 && part2 > 0 {
			break
		}
	}

	fmt.Printf("Part 1: %d\n", part1)
	fmt.Printf("Part 2: %d\n", part2)
}

A advent_of_code/2022/input15.txt => advent_of_code/2022/input15.txt +29 -0
@@ 0,0 1,29 @@
Sensor at x=2557568, y=3759110: closest beacon is at x=2594124, y=3746832
Sensor at x=2684200, y=1861612: closest beacon is at x=2816974, y=2000000
Sensor at x=1003362, y=1946094: closest beacon is at x=1972523, y=2563441
Sensor at x=2142655, y=1481541: closest beacon is at x=1932524, y=967542
Sensor at x=2796219, y=1955744: closest beacon is at x=2816974, y=2000000
Sensor at x=3890832, y=1818644: closest beacon is at x=3454717, y=2547103
Sensor at x=2828842, y=1921726: closest beacon is at x=2816974, y=2000000
Sensor at x=2065227, y=583957: closest beacon is at x=1932524, y=967542
Sensor at x=2725784, y=2088998: closest beacon is at x=2816974, y=2000000
Sensor at x=3574347, y=927734: closest beacon is at x=1932524, y=967542
Sensor at x=2939312, y=2652370: closest beacon is at x=3454717, y=2547103
Sensor at x=2495187, y=3681541: closest beacon is at x=2431306, y=3703654
Sensor at x=2878002, y=2054681: closest beacon is at x=2816974, y=2000000
Sensor at x=1539310, y=3235516: closest beacon is at x=1972523, y=2563441
Sensor at x=545413, y=533006: closest beacon is at x=-538654, y=69689
Sensor at x=1828899, y=3980292: closest beacon is at x=2431306, y=3703654
Sensor at x=3275729, y=2937931: closest beacon is at x=3454717, y=2547103
Sensor at x=600131, y=3861189: closest beacon is at x=2431306, y=3703654
Sensor at x=2089895, y=28975: closest beacon is at x=1932524, y=967542
Sensor at x=2960402, y=3942666: closest beacon is at x=2594124, y=3746832
Sensor at x=3785083, y=3905392: closest beacon is at x=2594124, y=3746832
Sensor at x=1721938, y=1077173: closest beacon is at x=1932524, y=967542
Sensor at x=2515156, y=3751221: closest beacon is at x=2594124, y=3746832
Sensor at x=2469423, y=2109095: closest beacon is at x=2816974, y=2000000
Sensor at x=1776986, y=904092: closest beacon is at x=1932524, y=967542
Sensor at x=2789294, y=3316115: closest beacon is at x=2594124, y=3746832
Sensor at x=3538757, y=2695066: closest beacon is at x=3454717, y=2547103
Sensor at x=2299738, y=2708004: closest beacon is at x=1972523, y=2563441
Sensor at x=2388366, y=3234346: closest beacon is at x=2431306, y=3703654