lol nice, at least it works for the test cases

$this->check(basicOp('/', 4, 0), 0);

Division by zero :(

Sorry but this is not best practices. Sure it looks pretty with it being only a few lines of code but it's O(n^2) whereas my solution is O(n).

Let n = 10000;
Runtime for this solution ~= 0.0433 seconds
Runtime for my solution ~= 0.0017 seconds

Let n = 100000;
Runtime for this solution ~= 4.8142 seconds
Runtime for my solution ~= 0.0169 seconds

Let n = 1000000;
Runtime for this solution == Fails (out of memory after running locally for over 15 minutes)
Runtime for my solution ~= 0.1612 seconds