10. Quiz: Untouched Fields

10 Untouched Fields QUIZ RENDER V2

QUESTION:

Given the above constraints, after taking all of these measurements into account, how many of the 30 grid cells in the constraint matrices are never changed (and remain 0)? The answer should be a single integer.

SOLUTION:

NOTE: The solutions are expressed in RegEx pattern. Udacity uses these patterns to check the given answer