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Cover image for DAY 2 - Advent of Code 2020 w/ GoLang

DAY 2 - Advent of Code 2020 w/ GoLang

dizveloper profile image Edvin Updated on ・1 min read

DAY 2:
You can’t access indices of a string like an array. They are immutable. You’ll need to convert it to a rune or byte array.

package days

import (
    "fmt"
    "strconv"
    "strings"

    inputs "../inputs"
)

// Two : advent of code, day two part1 and 2.
func Two() {
    inputSlice := inputs.Day2

    partOneSlice := []string{}
    partTwoSlice := []string{}

    for i := 0; i < len(inputSlice); i++ {
        rangeSlice := getRange(inputSlice[i])
        ruleAndPassSlice := getRuleAndPass(inputSlice[i])

        occurances := strings.Count(ruleAndPassSlice[1], ruleAndPassSlice[0])
        if occurances >= rangeSlice[0] && occurances <= rangeSlice[1] {
            partOneSlice = append(partOneSlice, inputSlice[i])
        }

        if checkIndices(ruleAndPassSlice[1], []rune(ruleAndPassSlice[0])[0], rangeSlice[0], rangeSlice[1]) {
            partTwoSlice = append(partTwoSlice, inputSlice[i])
        }

    }

    fmt.Print("Part 1: ")
    fmt.Println(len(partOneSlice))

    fmt.Print("Part 2: ")
    fmt.Println(len(partTwoSlice))
}

func checkIndices(in string, r rune, first int, last int) bool {
    toRune := []rune(in)
    return ((toRune[first-1] == r && toRune[last-1] != r) || (toRune[first-1] != r && toRune[last-1] == r))
}

func getRange(input string) []int {
    splitter := strings.Split(input, " ")
    rangeAsStrings := strings.Split(splitter[0], "-")

    rangeAsInts := make([]int, len(rangeAsStrings))

    for i, s := range rangeAsStrings {
        rangeAsInts[i], _ = strconv.Atoi(s)
    }

    return rangeAsInts
}

func getRuleAndPass(input string) []string {
    splitter := strings.Split(input, " ")
    ruleAndPass := []string{strings.Replace(splitter[1], ":", "", -1), splitter[2]}

    return ruleAndPass
}

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Link to Github source file

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