message: Update build-a-matrix-with-conditions.py
diff: -# Time: O(k + r + c), r = len(rowConditions), c = len(colConditions)
  +# Time: O(k^2 + r + c), r = len(rowConditions), c = len(colConditions)
  # Space: O(k + r + c)
  # topological sort
  @@ -33,8 +33,10 @@ class Solution(object):
  return result
  row_order = topological_sort(rowConditions)
  + if len(row_order) != k:
  + return []
  col_order = topological_sort(colConditions)
  - if not (len(row_order) == k and len(col_order) == k):
  + if len(col_order) != k:
  return []
  row_idx = {x:i for i, x in enumerate(row_order)}
  col_idx = {x:i for i, x in enumerate(col_order)}
  