ports - sav

lib/matrix_convert_to_zero.rb

@@ -3,8 +3,47 @@
 # 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(n) where n is the number of total elements in the matrix
+# Space complexity: O(1) done in place
 def matrix_convert_to_zero(matrix)
-  raise NotImplementedError
+  placeholder_substitution(matrix, 0, -1)
+  convert(matrix)
+  placeholder_substitution(matrix, -1, 0)
+end
+
+def placeholder_substitution(matrix, elem_to_sub, subber)
+  matrix.length.times do |row|
+    matrix[row].length.times do |col|
+      matrix[row][col] = subber if matrix[row][col] == elem_to_sub
+    end
+  end
+end
+
+def convert(matrix)
+  i = 0
+  while i < matrix.length
+    j = 0
+    while j < matrix[i].length
+      if matrix[i][j] == -1
+        set_row_to_zero(i, matrix)
+        set_column_to_zero(j, matrix)
+      end
+      j += 1
+    end
+    i += 1
+  end
+end
+
+def set_row_to_zero(row, matrix)
+  return if !row || !matrix
+  matrix[row].map! do |elem|
+    elem == -1 ? -1 : 0
+  end
+end
+
+def set_column_to_zero(col, matrix)
+  return if !col || !matrix
+  matrix.each do |row|
+    row[col] = 0 unless row[col] == -1
+  end
 end