I think it’s O(n) because I put in n = 2 to 20, so I could see the times for a 16-letter isogram, though the longest is a 17-letter word. SUBDERMATOGLYPHIC.

Anywho, looking at that graph, I reasoned the amounts of time for a 16 letter isogram:

Time for 1 n = ~ 1.25

N

Need 16 n’s, so 1.25 * 16 = **20** to do O(n).

N LOG N

n log n + 20 = **70**, (50 + 20) = n log n + n

N^2

n^2 - n/2 = 256 - 20/2 = **118** for n^2

*20 = O(n) = FASTEST*

That’s my vote.