diff --git a/lib/matrix_convert_to_zero.rb b/lib/matrix_convert_to_zero.rb
index 4fb139c..54676de 100644
--- a/lib/matrix_convert_to_zero.rb
+++ b/lib/matrix_convert_to_zero.rb
@@ -3,8 +3,64 @@
 # If any number is found to be 0, the method updates all the numbers in the
 # corresponding row as well as the corresponding column to be 0.
 
-# Time complexity: ?
-# Space complexity: ?
+# Time complexity: O(nm) where m is the length of a column and n is the length of a row of the matrix
+# Space complexity: O(1) because it is done in place and there are no arrays, etc being stored in memory within the method
 def matrix_convert_to_zero(matrix)
-  raise NotImplementedError
+  convert_one_to_x_where_zero_is_found(matrix)
+  convert_x_to_zero(matrix)
+  return matrix
+end
+
+# helper methods
+def convert_column_to_x(matrix, j)
+  n = 0
+  while matrix[n] != nil
+    if matrix[n][j] == 1
+      matrix[n][j] = "X"
+    end
+    n += 1
+  end
+  return matrix
+end
+
+def convert_row_to_x(matrix, i)
+  m = 0
+  while matrix[i][m] != nil
+    if matrix[i][m] == 1
+      matrix[i][m] = "X"
+    end
+    m += 1
+  end
+  return matrix
+end
+
+def convert_one_to_x_where_zero_is_found(matrix)
+  i = 0
+  while matrix[i] != nil
+    j = 0
+    while matrix[i][j] != nil
+      if matrix[i][j] == 0
+        convert_column_to_x(matrix, j)
+        convert_row_to_x(matrix, i)
+      end
+      j += 1
+    end
+    i += 1
+  end
+  return matrix
+end
+
+def convert_x_to_zero(matrix)
+  i = 0
+  while matrix[i] != nil
+    j = 0
+    while matrix[i][j] != nil
+      if matrix[i][j] == "X"
+        matrix[i][j] = 0
+      end
+      j += 1
+    end
+    i += 1
+  end
+  return matrix
 end