Melissa : Matrix convert to zero

[melicious-dish]

No description provided.

[shrutivanw]

Nicely done! 👍

Since the number of rows, let's say n may not be equal to number of columns, let's say m, speak to the time and space complexities in terms n and m instead of in terms of just n. Also, always describe what n and m stand for.

So, the time complexity of your algorithm will be O(n * m).

You can imagine a scenario where all the values in the input matrix are zero. In this scenario, the size of zeros_array in your algorithm will be n * m. You could optimize this by tracking the columns that you want to make zero in an array of size m and setting the value at index in that array to true if the column needs to be made zero. i.e.

• change line 8 to zeros_array = Array.new(matrix[0].length, false)
• change line 14 to zeros_array[index] = true
• change lines 22 through 28 to:

  matrix.length.times do |row|
    matrix[0].length.times do |column|
      if zeros_array[column] == true
        matrix[row][column] = 0
      end
    end
  end
  return # since the matrix is modified in place, no need to return matrix

The only further optimization I could think of is to use row 0 and column 0 in the input matrix to track what needs to be converted to 0. Here's what I came up with: https://github.com/Ada-C10/matrix_convert_to_zero/blob/solution/lib/matrix_convert_to_zero.rb