ianadiwibowo/central-park

package main

import "math"

func FlippingBits(input int64) int64 {
    binary := convertDecimalToBinary(input)
    binary = padLeftWithZero(binary, 32-len(binary))
    binary = flip(binary)

    return convertBinaryToDecimal(binary)
}

func convertDecimalToBinary(decimal int64) (binary []int64) {
    if decimal == 0 {
        return []int64{0}
    }

    for decimal != 0 {
        binary = append([]int64{decimal % 2}, binary...)
        decimal = decimal / 2
    }

    return binary
}

func padLeftWithZero(binary []int64, zeroCount int) []int64 {
    prefix := make([]int64, zeroCount)

    return append(prefix, binary...)
}

func flip(binary []int64) []int64 {
    flippedBinary := make([]int64, len(binary))

    for i, v := range binary {
        flippedBinary[i] = flipBit(v)
    }

    return flippedBinary
}

func flipBit(bit int64) int64 {
    if bit == 0 {
        return 1
    } else {
        return 0
    }
}

func convertBinaryToDecimal(binary []int64) int64 {
    var decimal int64

    for i, b := range binary {
        power := len(binary) - 1 - i
        decimal += int64(math.Pow(2, float64(power))) * b
    }

    return decimal
}