Function to calculate the minimum XOR of at most K elements in [ L , R ]
int minimumXor ( int L , int R , int K ) { if ( K > 4 ) return 0 ; else if ( K == 4 ) return func4 ( L , R , K ) ; else if ( K == 3 ) return func3 ( L , R , K ) ; else if ( K == 2 ) return func2 ( L , R , K ) ; else return L ; }