Sockets - Jansen

lib/matrix_convert_to_zero.rb

@@ -3,8 +3,71 @@
 # 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(r * c), where r equals the number of arrays (rows) inside the array, and
+#                    c equals the number of elements (columns) inside of a nested array
+# Space complexity: O(1), or constant.  We're not creating any additional data structures that hinges on user input
 def matrix_convert_to_zero(matrix)
-  raise NotImplementedError
+  # Check for edge cases
+  return if (matrix == nil || matrix == [])
+
+  # Determine length of rows and columns
+  rows = matrix.length
+  columns = matrix[0].length
+
+  row_zero_zeroes = false
+  # Does Row 0 have zeros?
+  columns.times do |col|
+    if matrix[0][col] == 0
+      row_zero_zeroes = true
+    end
+  end
+
+  column_zero_zeroes = false
+  # Does Column 0 have zeros?
+  rows.times do |row|
+    if matrix[row][0] == 0
+      column_zero_zeroes = true
+    end
+  end
+
+  # Check (Rows 1 - n) and (Cols 1 - n)
+  # Track found zeros through Row 0 and Col 0
+  # (by changing corresponding element into 0)
+
+  (rows - 1).times do |row|
+    (columns - 1).times do |col|
+      if matrix[row + 1][col + 1] == 0
+        matrix[0][col + 1] = 0
+        matrix[row + 1][0] = 0
+      end
+    end
+  end
+
+  # Look at an element inside matrix
+  # Check corresponding element inside row 0 or col 0
+  # Are either 0?  If so, change targeted element to 0
+
+  (rows - 1).times do |row|
+    (columns - 1).times do |col|
+      if matrix[0][col + 1] == 0 || matrix[row + 1][0] == 0
+        matrix[row + 1][col + 1] = 0
+      end
+    end
+  end
+
+  # IF Row 0 has zeros: Populate with 0
+  if row_zero_zeroes
+    columns.times do |col|
+      matrix[0][col] = 0
+    end
+  end
+
+  # IF Col 0 has zeros:  Populate with 0
+  if column_zero_zeroes
+    rows.times do |row|
+      matrix[row][0] = 0
+    end
+  end
+
+  return matrix
 end