Python:
File "/workspace/default/tests.py", line 40, in d2
Test.expect(False, "Should support comparison")
^^^^
NameError: name 'Test' is not defined
Loool

The type of function result in solution blank should be at least long int. Because we can have list like {2^30-1, 2^30-2, 2^30-3, 2^30-4, 2^30-5}. Then the int answer will not be 5_368_709_105. Maybe it will be -25, maybe 2_147_483_647. In any case, this shows well that the author did not really think about the problem.

IMHO, localmax and globalmax should be more than int (long int, for example). Because we can have list like {2^30-1, 2^30-2, 2^30-3, 2^30-4, 2^30-5}. Then the answer will be 2_147_483_647 and not 5_368_709_105.