This is a elegand way of putting the solution. where can I read on such syntax

Should be fixed. Yell if it isn't.

beautiful

I second that. Got with array [289, 18, 306, 17, 17, 255, 15, 270] error: expected: <270> but was: <18>

C translation with a #define instead of a typedef and symbolic 'constant' EIGHT for 8? Not really best practice.

Java

The random tests are incorrect and do not match the condition "A < B < C < D" (for example - new int[] {9, 45, 81, 5, 9, 45, 5, 25}

At least it's the program and not like most other solutions where people just tried to deceive the weak unit tests

Nice idea!

genius