aoc2023/day-11/util.go

package main

import (
	"bufio"
	"log"
	"os"
	"strings"
)

// readlines reads lines from stdin.
// returns input as an array of strings
func readlines() []string {
	lines := []string{}

	scanner := bufio.NewScanner(os.Stdin)
	for scanner.Scan() {
		lines = append(lines, scanner.Text())
	}

	if err := scanner.Err(); err != nil {
		log.Fatal(err)
	}

	return lines
}

// parseInput stores coordinates of galaxies
// stores empty row and column indexes
func parseInput(lines []string) {
	x := 0
	runes = make([][]rune, len(lines))
	for i, line := range lines {
		for j, r := range line {
			runes[i] = append(runes[i], r)
			if r == '#' {
				galaxies = append(galaxies, newGalaxy(x, j, i))
				x++
			}
		}
	}

	for i := range lines {
		if strings.Count(lines[i], "#") == 0 {
			empty["row"] = append(empty["row"], i)
		}
	}

	f := func(i int) bool {
		for _, line := range lines {
			if line[i] == '#' {
				return false
			}
		}
		return true
	}

	for i := range lines[0] {
		if f(i) {
			empty["col"] = append(empty["col"], i)
		}
	}
}

// inCompared returns true if both i, j coords are in compared
func inCompared(i, j int, compared [][]int) bool {
	for _, comp := range compared {
		if contains(comp, i) && contains(comp, j) {
			return true
		}
	}
	return false
}

// contains returns true if a slice of elements contains a given element
func contains[T comparable](elems []T, v T) bool {
	for _, s := range elems {
		if v == s {
			return true
		}
	}
	return false
}