I have tried a long time to understand the following problem. I have also read the tutorial ans comments but everything is unclear to me. I have tried it in papers too. But not getting it.Can anyone please help me to understand the following problem? Thanks in advance.








First of all you have to get all dancing pairs then you should calculate the complexity of a pairs' assignment.
for the first test case the dancing pairs are:
(0,3) where 3 = 0 XOR 11
(1,2) where 2 = 1 XOR 11
(2,1) where 1 = 2 XOR 11
(3,0) where 0 = 3 XOR 11
then we look at each pair of dancing pair (a,b) and (c,d) such taht a < c and b > d and we find those pairs (0,3) and (1,2)
(0,3) and (2,1)
(0,3) and (3,0)
(1,2) and (2,1)
(1,2) and (3,0)
(2,1) and (3,0)