https://ide.codingblocks.com/s/61546
https://hack.codingblocks.com/contests/c/537/875
Even though I understand the problem is given for recursion but I have tried a different approach using set bits.
Instead of looking at the combinations in question as that of ‘a’ and ‘b’ , if we look at them as ‘a’ as 0 and ‘b’ as 1 then we only have to count the number of numbers < (2^n) having no consecutive set bits. This is my approach. Please tell if my approach is wrong and if not then point out the problem with my code please.