fun main() {
val n = 90
println("Input: ${toBitString(n, 8)}")
val result = swapsOddAndEvenBits(n)
println("Result: ${toBitString(result, 8)}")
}
/**
* Swaps odd and even bits in a 32-bit integer.
*/
fun swapsOddAndEvenBits(n: Int): Int {
// Mask to isolate odd bits: binary 101010... (hex: 0xAAAAAAAA)
val oddBits = n and 0xAAAAAAAA.toInt()
// Mask to isolate even bits: binary 010101... (hex: 0x55555555)
val evenBits = n and 0x55555555
println("oddBits: ${toBitString(oddBits, 8)}")
println("evenBits: ${toBitString(evenBits, 8)}")
// Shift odd bits right to move them to even positions
val shiftedOddBits = oddBits ushr 1
// Shift even bits left to move them to odd positions
val shiftedEvenBits = evenBits shl 1
println("oddBits Right-shift: ${toBitString(shiftedOddBits, 8)}")
println("evenBits Left-shift: ${toBitString(shiftedEvenBits, 8)}")
// Combine the shifted bits
return shiftedOddBits or shiftedEvenBits
}
/**
* Converts an integer to a binary string with fixed width.
* Pads with leading zeros to match the desired bit width.
*/
fun toBitString(n: Int, width: Int): String {
val binary = Integer.toBinaryString(n)
return binary.takeLast(width).padStart(width, '0')
}
/*
run:
Input: 01011010
oddBits: 00001010
evenBits: 01010000
oddBits Right-shift: 00000101
evenBits Left-shift: 10100000
Result: 10100101
*/
