The idea with the selection of all options will not work. Apparently a formula or equivalent is needed. How to decide?

Question

C++ / C#

Here

Answer 1

Iterate over a and b. Then see what values ​​c can take so that the constraints are met. This will be a segment of numbers. They do not need to be sorted out - you can immediately calculate them all. For example, if you see that c<=10 satisfies the constraints, then there are ten triples with the current a, b.