/*
Six different functions that accept 5 or 7
and return the other number, without using if/when.
*/
// 1. Arithmetic sum trick: 5 + 7 = 12
fun flipSum(x: Int): Int =
12 - x
// 2. Product trick: 5 * 7 = 35
fun flipProduct(x: Int): Int =
35 / x
// 3. XOR trick: 5 xor 7 = 2
// x xor 2 flips 5 ↔ 7
fun flipXor(x: Int): Int =
x xor 2
// 4. Modulo-based trick using divisibility:
// x % 7 == 0 → x is 7
// x % 5 == 0 → x is 5
// Boolean → Int via .compareTo(false) or .let { if (it) 1 else 0 }
fun flipMod(x: Int): Int =
5 * (x % 7 == 0).compareTo(false) +
7 * (x % 5 == 0).compareTo(false)
// 5. Absolute-value trick: |x - 12| flips 5 ↔ 7
fun flipAbs(x: Int): Int =
kotlin.math.abs(x - 12)
// 6. Array lookup using arithmetic index:
// For x = 5 → (5 - 5) / 2 = 0 → table[0] = 7
// For x = 7 → (7 - 5) / 2 = 1 → table[1] = 5
fun flipArray(x: Int): Int {
val table = arrayOf(7, 5)
val index = (x - 5) / 2
return table[index]
}
fun main() {
println("flip_sum(5) = ${flipSum(5)}")
println("flip_sum(7) = ${flipSum(7)}")
println()
println("flip_product(5) = ${flipProduct(5)}")
println("flip_product(7) = ${flipProduct(7)}")
println()
println("flip_xor(5) = ${flipXor(5)}")
println("flip_xor(7) = ${flipXor(7)}")
println()
println("flip_mod(5) = ${flipMod(5)}")
println("flip_mod(7) = ${flipMod(7)}")
println()
println("flip_abs(5) = ${flipAbs(5)}")
println("flip_abs(7) = ${flipAbs(7)}")
println()
println("flip_array(5) = ${flipArray(5)}")
println("flip_array(7) = ${flipArray(7)}")
}
/*
OUTPUT:
flip_sum(5) = 7
flip_sum(7) = 5
flip_product(5) = 7
flip_product(7) = 5
flip_xor(5) = 7
flip_xor(7) = 5
flip_mod(5) = 7
flip_mod(7) = 5
flip_abs(5) = 7
flip_abs(7) = 5
flip_array(5) = 7
flip_array(7) = 5
*/
