I do not think there is an issue here ? the Ruby reference solution returns 1 for args_count("abc").

[NORTH SOUTH SOUTH EAST WEST NORTH]
[SOUTH EAST WEST NORTH]
[SOUTH NORTH]
[]

The second case doesn't comply to:

(W<->E or S<->N side by side)

Maybe this helps (written by dulot):

Think of NORTH, SOUTH, WEST, EAST as chemical products. When NORTH and SOUTH or WEST and EAST are side by side they annihilate each other; they don't if they are separated by another element.

They're not, please, read the instructions again, specially, the Note at the end. That exact case is explained there.

not an issue, your algo is just too bad slow. ;)

That's a "performance" kata specifically for that reason.