import scala.util.Random
/*
Generate N random 1s in a zero-based matrix.
Strategy:
- Treat the matrix as a flat index space [0 until rows*cols].
- Randomly pick unique positions using a Set to ensure uniqueness.
- Convert each chosen flat index back to (row, col).
- This avoids repeatedly searching for empty cells and keeps the logic simple.
*/
// Allocate a rows×cols matrix initialized to zero
def allocateMatrix(rows: Int, cols: Int): Array[Array[Int]] = {
// Array.fill keeps the code compact and expressive
Array.fill(rows, cols)(0)
}
// Print the matrix
def printMatrix(matrix: Array[Array[Int]]): Unit = {
matrix.foreach { row =>
println(row.mkString(" "))
}
}
// Generate N random 1s in a zero-based matrix
def generateRandomMatrix(rows: Int, cols: Int, count: Int): Array[Array[Int]] = {
val total: Int = rows * cols
if (count > total)
throw new IllegalArgumentException("Requested more 1s than available cells.")
val matrix: Array[Array[Int]] = allocateMatrix(rows, cols)
// Use a Set to ensure unique positions
var chosen: Set[Int] = Set.empty
val rng: Random = new Random()
// Draw unique positions
while (chosen.size < count) {
val index: Int = rng.nextInt(total)
chosen += index
}
// Convert flat indices to (row, col)
chosen.foreach { index =>
val r: Int = index / cols
val c: Int = index % cols
matrix(r)(c) = 1
}
matrix
}
// Example usage
@main def run(): Unit = {
val rows: Int = 5
val cols: Int = 7
val numberOfOnes: Int = 10
val result: Array[Array[Int]] = generateRandomMatrix(rows, cols, numberOfOnes)
printMatrix(result)
}
/*
run:
0 0 1 0 1 0 0
0 0 0 1 1 1 1
0 0 0 1 0 0 0
0 0 1 0 0 0 1
0 0 0 0 0 1 0
*/
