Alice Hsiao - Matrix Convert to Zero

[alicehsiao]

No description provided.

[shrutivanw]

Nice work!

The time complexity explanation is correct.
Imagine a scenario where all the values in your input matrix are zeroes. In this case, you'll end adding the index values of each cell into the zeros array. This means the space complexity of your algorithm is O(n*m) where n is the number of rows and m is the number of columns in the input parameter, matrix.

You could optimize the space complexity by instead tracking one array of size n to track the rows that need to be converted to 0s, and another array of size m to track the columns that need to be converted to 0s. Initialize them to false and make the corresponding ior jindex true in the row tracking matrix or column tracking matrix if matrix[i][j] is 0. This would reduce your space complexity to O(n+m) where n is the number of rows and m is the number of columns in the input parameter, matrix.

The only further optimization I could think of was to use the 0th row and the 0th column to track which columns and rows to convert to zero and make the space complexity O(1). Here's my solution: https://github.com/Ada-C10/matrix_convert_to_zero/blob/solution/lib/matrix_convert_to_zero.rb