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60 lines
1.5 KiB
Go
60 lines
1.5 KiB
Go
package codes
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import (
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"fmt"
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)
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type UserCode int
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func intPow(n, m int) int {
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if m == 0 {
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return 1
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}
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result := n
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for i := 2; i <= m; i++ {
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result *= n
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}
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return result
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}
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var numberToChar = [...]rune{'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'}
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func CodeToString(code UserCode) (string, error) {
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toReturn := [4]rune{'A', 'A', 'A', 'A'}
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value := int(code)
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for place := 3; place >= 0; place-- {
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index := 3 - place
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currentPlaceValue := value / intPow(36, place)
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value -= currentPlaceValue * intPow(36, place)
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if currentPlaceValue >= len(numberToChar) { return "", fmt.Errorf("Failed to generate usercode %d to string, currentPlaceValue %d and length of number to char %d in place %d", code, currentPlaceValue, len(numberToChar),place ) }
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toReturn[index] = numberToChar[currentPlaceValue]
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}
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return string(toReturn[:]), nil
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}
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func ParseUserCode(s string) (UserCode, error) {
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asRune := []rune(s)
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if len(asRune) != 4 { return 0, fmt.Errorf("String to deconvert is not of length 4: %s", s) }
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var toReturn UserCode = 0
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for place := 3; place >= 0; place-- {
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index := 3 - place
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curDigitNum := 0
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found := false
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for i, letter := range numberToChar {
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if letter == asRune[index] {
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curDigitNum = i
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found = true
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}
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}
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if !found { return 0, fmt.Errorf("Failed to find place's number %s", s) }
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toReturn += UserCode(curDigitNum * intPow(36, place))
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}
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return toReturn, nil
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}
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