Are They Same-Divide and conquer

#1

ques-Two strings a and b of equal length are called equivalent in one of the two cases:

They are equal. 2 .If we split string a into two halves of the same size a1 and a2, and string b into two halves of the same size b1 and b2, then one of the following is correct: 1 . a1 is equivalent to b1, and a2 is equivalent to b2 2 . a1 is equivalent to b2, and a2 is equivalent to b1

my code-https://ide.codingblocks.com/s/100722

my code is giving no output pls resolve the problem.

#2 
 return ( isequivalent(a1, b1, n, m) || isequivalent(a2, b2, n, m) || 
                isequivalent(a1, b2, n, m) || isequivalent(a2, b1, n, m) ) ;

you are again sending the same length in recursion call.