good function isPowerOf2

I tried to test the testFn from the "Test Cases". But the function is not working properly!

GOOD:

customers {100, 50, 90, 90, 60}

n 2

return 200

ERROR:

customers {100, 90, 90, 60, 50}

n 2

return 210

log:

100 0

100 90

100 180

160 180

210 180

but true way 100 + 90 =190 vs 90 + 60 + 50 = 200

true algorithm see (for n == 2):
https://www.geeksforgeeks.org/partition-a-set-into-two-subsets-such-that-the-difference-of-subset-sums-is-minimum/

I have tried something similar (but less elegant), however this algorithm does not pass the test with the dataset:

customers {100, 90, 90, 60, 50}
n 2

this algorithm return 210 (100+60+50 = 210 vs 90 + 90 =180)
but true result: 200 (100 + 90 = 190 vs 90 + 60 + 50 = 200)