Four Digit room code to integer

room.go

// https://go.dev/play/p/CxJf4Jf9rDZ

package main

import (
	"fmt"
	"strings"
)

const ZZZZ = 18279 + 456975
const AAAA = 18279

func numberToEncodedLetter(number int64) string {
	dictionary := getDictionary()
	index := int(number) % len(dictionary)
	quotient := number / int64(len(dictionary))
	var result string

	if number <= int64(len(dictionary)) {
		return numToLetter(int(number), dictionary) // Number is within single digit bounds of our encoding letter alphabet
	}

	if quotient >= 1 {
		// This number was bigger than our dictionary, recursively perform this function until we're done
		if index == 0 {
			quotient-- // Accounts for the edge case of the last letter in the dictionary string
		}
		result = numberToEncodedLetter(quotient)
	}

	if index == 0 {
		index = len(dictionary) // Accounts for the edge case of the final letter; avoids getting an empty string
	}

	return result + numToLetter(index, dictionary)
}

func numToLetter(number int, dictionary []string) string {
	// Takes a letter between 0 and max letter length and returns the corresponding letter
	if number > len(dictionary) || number < 0 {
		return ""
	}
	if number == 0 {
		return ""
	} else {
		return dictionary[number-1]
	}
}

func getDictionary() []string {
	return strings.Split("ABCDEFGHIJKLMNOPQRSTUVWXYZ", "")
}

func main() {
	// Example usage
	fmt.Println(numberToEncodedLetter(475254))
}