/*
Select N unique random indices from an existing array in Kotlin.
Return the indices and print both the index and the corresponding value.
Approach:
- Build a list of indices: 0, 1, 2, ..., size-1.
- Shuffle the list using shuffled() (Fisher–Yates internally).
- Take the first N shuffled indices — guaranteed unique.
- Return those indices to the caller.
*/
/** Return N unique random indices */
fun pickUniqueIndices(arraySize: Int, count: Int): List<Int> {
if (count > arraySize) {
throw IllegalArgumentException("Cannot pick more unique indices than array size.")
}
// Build index list
val indices: List<Int> = (0 until arraySize).toList()
// Shuffle and take first N
return indices.shuffled().take(count)
}
fun main() {
// Example array
val data: IntArray = intArrayOf(
5, 12, 5, 19, 5, 33, 47, 5, 58, 61, 17, 3, 5, 74, 83, 90, 6
)
val n: Int = 6 // number of unique indices to pick
// Get unique random indices
val indices: List<Int> = pickUniqueIndices(data.size, n)
// Print results
println("Random unique indices and their values:")
for (idx in indices) {
println("index $idx -> value ${data[idx]}")
}
}
/*
run:
Random unique indices and their values:
index 8 -> value 58
index 9 -> value 61
index 12 -> value 5
index 15 -> value 90
index 7 -> value 5
index 14 -> value 83
*/
