You can’t, that’s part of the challenge.
You need to create your own test data and run it through your program. Compare what your program gives with the correct answer. In order to determine what the correct answer should be, it may help to write a simple brute force solver.
Alternatively, head on over to spojtoolkit.com, and compare your answers with theirs. Beware though, there are plenty of programs on spojtoolkit that give incorrect answers, and there are many invalid test cases available.
