Count Unique Values

The dashboard shows one fewer unique visitor than the database does.

Given a sorted array, return how many unique values it contains.

Fix the code so every test passes. Keep the function name countUnique.

Test cases

• countUnique([1,1,1,2,3,3,4,4,5,6]) → 6
• countUnique([]) → 0
• countUnique([7]) → 1
• countUnique([-2,-1,-1,0,1]) → 4

Stuck? Hints go from a nudge to the exact fix.