aoc2023/day-11/one.go

package main

import (
	"math"

	log "github.com/sirupsen/logrus"
)

var runes = [][]rune{}

type coords struct {
	X int
	Y int
}

type galaxy struct {
	identifier int
	coords
}

func newGalaxy(identifier, x, y int) galaxy {
	return galaxy{identifier: identifier, coords: coords{X: x, Y: y}}
}

var galaxies = make([]galaxy, 0)

var empty = map[string][]int{
	"row": {},
	"col": {},
}

// shortestRoute calculates horizontal and vertical distances between points
// if empty row or columns exist then horz and vert are padded
// returns the sum of both distances
func shortestRoute(a, b coords, factor int) int {
	horz := int(math.Abs(float64(b.X - a.X)))
	vert := int(math.Abs(float64(b.Y - a.Y)))

	for _, row := range empty["row"] {
		if row >= a.Y && row < b.Y || row >= b.Y && row < a.Y {
			log.Debug("empty row, adding to vert")
			vert += (factor - 1)
		}
	}
	for _, col := range empty["col"] {
		if col >= a.X && col < b.X || col >= b.X && col < a.X {
			log.Debug("empty col, adding to horz")
			horz += (factor - 1)
		}
	}

	return int(math.Abs(float64(horz + vert)))
}

// one returns the sum of all shortest distances between galaxies
func one(lines []string) int {
	parseInput(lines)

	compared := [][]int{}
	sum := 0
	for i := range galaxies {
		for j := range galaxies {
			if i == j || inCompared(i, j, compared) {
				continue
			}

			compared = append(compared, []int{galaxies[i].identifier, galaxies[j].identifier})
			sum += shortestRoute(galaxies[i].coords, galaxies[j].coords, 2)
		}
	}

	return sum
}