| Codeforces Round #383 (Hard) |
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| Finished |
There are some beautiful girls in Arpa’s land as mentioned before.
Once Arpa came up with an obvious problem:
Given an array and a number x, count the number of pairs of indices i, j (1 ≤ i < j ≤ n) such that
, where
is bitwise xor operation.
Immediately, Mehrdad discovered a terrible solution that nobody trusted. Now Arpa needs your help to implement the solution to that problem.
First line contains two integers n and x (1 ≤ n ≤ 2·106, 0 ≤ x ≤ 2107) — the number of elements in the array and the integer x.
Second line contains n integers a1, a2, ..., an (1 ≤ ai ≤ 2107) — the elements of the array. It's guaranteed that
.
Input compression : x and ais are given in 32 base numerical system (i.e. "V" = 31, "H9" = 17·32 + 9 = 480).
It's guaranteed that no number starts with zero in the input.
Print a single integer: the answer to the problem.
2 3
1 2
1
4 1
A C E F
1
A bitwise xor takes two bit integers of equal length and performs the logical xor operation on each pair of corresponding bits. The result in each position is 1 if only the first bit is 1 or only the second bit is 1, but will be 0 if both are 0 or both are 1. You can read more about bitwise xor operation here: https://en.wikipedia.org/wiki/Bitwise_operation#XOR.
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