using System;
class RandomOnesMatrix
{
/*
Generate N random 1s in a zero-based matrix.
Strategy:
- Treat the matrix as a flat index space [0 .. rows*cols - 1].
- Randomly pick unique positions using a Boolean helper array.
- Convert each chosen flat index back to (row, col).
- This avoids repeatedly searching for empty cells and keeps the logic simple.
*/
// Print the matrix
static void PrintMatrix(int[,] matrix, int rows, int cols)
{
for (int r = 0; r < rows; r++) {
for (int c = 0; c < cols; c++)
{
Console.Write(matrix[r, c] + " ");
}
Console.WriteLine();
}
}
// Allocate a rows×cols matrix initialized to zero
static int[,] AllocateMatrix(int rows, int cols)
{
// Elements are automatically initialized to zero
return new int[rows, cols];
}
// Generate N random 1s in a zero-based matrix
static int[,] GenerateRandomMatrix(int rows, int cols, int count)
{
int total = rows * cols;
if (count > total)
throw new ArgumentException("Requested more 1s than available cells.");
int[,] matrix = AllocateMatrix(rows, cols);
// Temporary array to mark chosen positions
bool[] chosen = new bool[total];
Random rnd = new Random();
// Draw unique positions
int placed = 0;
while (placed < count)
{
int index = rnd.Next(total);
if (!chosen[index]) {
chosen[index] = true;
placed++;
}
}
// Convert flat indices to (row, col)
for (int i = 0; i < total; i++)
{
if (chosen[i]) {
int r = i / cols;
int c = i % cols;
matrix[r, c] = 1;
}
}
return matrix;
}
static void Main()
{
int rows = 5;
int cols = 7;
int numberOfOnes = 10;
int[,] result = GenerateRandomMatrix(rows, cols, numberOfOnes);
PrintMatrix(result, rows, cols);
}
}
/*
run:
0 0 0 0 0 0 0
0 1 1 0 1 0 1
0 0 0 0 1 0 1
1 1 0 0 1 0 0
0 0 0 1 0 0 0
*/
