Unique Number - I @hb

#1

https://ide.codingblocks.com/s/33079
https://hack.codingblocks.com/contests/c/452/462

#2

You are not supposed to use any extra space.
So please modify your logic.
HINT:
Make use of xor operation
a xor a = 0
So if all numbers occur in pairs except one number, and we xor all numbers, then all pairs will give us 0 and 0 xor unique number = unique number.

So basically answer is xor of all n values.

Try it yourself.