AdventOfCode2021/day08/8b/main.go

package main

import (
	"bufio"
	"fmt"
	"os"
	"strings"
)

func main() {
	content := returnContent("../input")
	//content := returnContent("../testInput")

	//Assisted Solution

	/*struggled quite a bit on this challenge,
	looked at a pre-comepleted solution in order
	to get a valid answer */

	sum := 0

	for _, line := range *content {
		split := strings.Split(line, " | ")

		lhs := split[0]
		rhs := split[1]

		lhsDigits := strings.Fields(lhs)
		rhsDigits := strings.Fields(rhs)

		one := ""
		four := ""
		seven := ""
		eight := ""
		var len5 []string
		var len6 []string
		for _, digit := range lhsDigits {
			switch len(digit) {
			case 2:
				one = digit
			case 4:
				four = digit
			case 3:
				seven = digit
			case 7:
				eight = digit
			case 5:
				len5 = append(len5, digit)
			case 6:
				len6 = append(len6, digit)
			}
		}

		zero := ""
		six := ""
		nine := ""
		for _, digit := range len6 {
			switch inCommon(digit, four) {
			case 4:
				nine = digit
			case 3:
				if inCommon(digit, seven) == 3 {
					zero = digit
				} else {
					six = digit
				}
			}
		}

		two := ""
		three := ""
		five := ""
		for _, digit := range len5 {
			if inCommon(digit, nine) == 5 {
				if inCommon(digit, seven) == 3 {
					three = digit
				} else {
					five = digit
				}
			} else {
				two = digit
			}
		}

		var answerDigits [4]int
		for i, digit := range rhsDigits {
			if len(digit) == 6 && inCommon(digit, zero) == 6 {
				answerDigits[i] = 0
			} else if len(digit) == 2 && inCommon(digit, one) == 2 {
				answerDigits[i] = 1
			} else if len(digit) == 5 && inCommon(digit, two) == 5 {
				answerDigits[i] = 2
			} else if len(digit) == 5 && inCommon(digit, three) == 5 {
				answerDigits[i] = 3
			} else if len(digit) == 4 && inCommon(digit, four) == 4 {
				answerDigits[i] = 4
			} else if len(digit) == 5 && inCommon(digit, five) == 5 {
				answerDigits[i] = 5
			} else if len(digit) == 6 && inCommon(digit, six) == 6 {
				answerDigits[i] = 6
			} else if len(digit) == 3 && inCommon(digit, seven) == 3 {
				answerDigits[i] = 7
			} else if len(digit) == 7 && inCommon(digit, eight) == 7 {
				answerDigits[i] = 8
			} else {
				answerDigits[i] = 9
			}
		}

		sum += 1000*answerDigits[0] + 100*answerDigits[1] + 10*answerDigits[2] + answerDigits[3]
	}

	fmt.Println(sum)

}

func inCommon(a string, b string) (count int) {
	for _, m := range a {
		for _, n := range b {
			if m == n {
				count++
			}
		}
	}

	return count
}

func returnContent(path string) *[]string {
	//read file and return it as an array of integers

	file, err := os.Open(path)
	var content []string

	if err != nil {
		fmt.Println("Unlucky, the file didn't open")
		return &content
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		content = append(content, scanner.Text())
	}

	return &content
}