79 lines
1.4 KiB
Go
79 lines
1.4 KiB
Go
package abcex
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import (
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"fmt"
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"math"
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)
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var decToAbcex = map[int]string{
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0: "0", 1: "1", 2: "2", 3: "3", 4: "4", 5: "5", 6: "6", 7: "7",
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8: "8", 9: "9", 10: "a", 11: "b", 12: "c", 13: "d", 14: "e",
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15: "f", 16: "g", 17: "h", 18: "i", 19: "j", 20: "k", 21: "l",
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22: "m", 23: "n", 24: "o", 25: "p", 26: "q", 27: "r", 28: "s",
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29: "t", 30: "u", 31: "v", 32: "w", 33: "x", 34: "y", 35: "z",
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}
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var abcexToDec = flipMap()
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func reverse(s string) string {
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runes := []rune(s)
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for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
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runes[i], runes[j] = runes[j], runes[i]
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}
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return string(runes)
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}
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func flipMap() map[string]int {
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flipped := make(map[string]int)
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for i, val := range decToAbcex {
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flipped[val] = i
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}
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return flipped
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}
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func Encode(number int64) string {
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if number == 0 {
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return "0"
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}
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result := ""
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negative := false
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if number < 0 {
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number = number * (-1)
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negative = true
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}
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for number > 0 {
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result = fmt.Sprintf("%s%s", decToAbcex[int(number%36)], result)
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number /= 36
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}
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if negative {
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return "-" + result
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}
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return result
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}
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func Decode(str string) int64 {
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var result int64
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result = 0
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negative := false
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if string(str[0]) == "-" {
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negative = true
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str = str[1:]
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}
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str = reverse(str)
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for i, c := range str {
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result = int64(math.Pow(36, float64(i)))*int64(abcexToDec[string(c)]) + result
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}
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if negative {
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return result * (-1)
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}
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return result
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}
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