#
# 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 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.
#
require "set"
# Allocate a rows×cols matrix initialized to zero
def allocate_matrix(rows, cols)
# Array.new keeps the code compact and expressive
Array.new(rows) { Array.new(cols, 0) }
end
# Print the matrix
def print_matrix(matrix)
matrix.each do |row|
puts row.join(" ")
end
end
# Generate N random 1s in a zero-based matrix
def generate_random_matrix(rows, cols, count)
total = rows * cols
if count > total
raise ArgumentError, "Requested more 1s than available cells."
end
matrix = allocate_matrix(rows, cols)
# Use a Set to ensure unique positions
chosen = Set.new
# Draw unique positions
while chosen.size < count
index = rand(total) # rand(total) gives 0..total-1
chosen << index
end
# Convert flat indices to (row, col)
chosen.each do |index|
r = index / cols
c = index % cols
matrix[r][c] = 1
end
matrix
end
# Example usage
rows = 5
cols = 7
number_of_ones = 10
result = generate_random_matrix(rows, cols, number_of_ones)
print_matrix(result)
=begin
run:
0 1 0 0 0 0 1
1 0 0 0 1 0 0
0 0 1 1 1 1 0
0 0 0 0 0 0 0
0 1 0 0 0 1 0
=end
