Codeforces Round 167 (Div. 2)
B
Dima and Sequence
Codeforces
1400
原题
← AC →
翻译中…

Dima got into number sequences. Now he's got sequence $*a*_{1}, *a*_{2}, ..., *a*_{*n*}$, consisting of $*n*$ positive integers. Also, Dima has got a function $*f*(*x*)$, which can be defined with the following recurrence:

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  • $*f*(0) = 0$;
  • $*f*(2·*x*) = *f*(*x*)$;
  • $*f*(2·*x* + 1) = *f*(*x*) + 1$.
翻译中…

Dima wonders, how many pairs of indexes $(*i*, *j*)$ $(1 ≤ *i* < *j* ≤ *n*)$ are there, such that $*f*(*a*_{*i*}) = *f*(*a*_{*j*})$. Help him, count the number of such pairs.

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Input

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The first line contains integer $*n*$ $(1 ≤ *n* ≤ 10^{5})$. The second line contains $*n*$ positive integers $*a*_{1}, *a*_{2}, ..., *a*_{*n*}$ $(1 ≤ *a*_{*i*} ≤ 10^{9})$.

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The numbers in the lines are separated by single spaces.

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Output

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In a single line print the answer to the problem.

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Please, don't use the %lld specifier to read or write 64-bit integers in C++. It is preferred to use the cin, cout streams or the %I64d specifier.

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Note

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In the first sample any pair $(*i*, *j*)$ will do, so the answer is $3$.

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In the second sample only pair $(1, 2)$ will do.

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样例

Input #1
3
1 2 4
Output #1
3
InputCopy OutputCopy
Input #2
3
5 3 1
Output #2
1
InputCopy OutputCopy
题目信息
题号
272B
时间限制
2 s
内存限制
256 MB
标签
模拟
数学

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