Problem:
Score : 400 points

Problem Statement

We have N integers. The i-th integer is A_i.

Find \sum_{i=1}^{N-1}\sum_{j=i+1}^{N} (A_i \mbox{ XOR } A_j), modulo (10^9+7).

What is \mbox{ XOR }?

The XOR of integers A and B, A \mbox{ XOR } B, is defined as follows:

When A \mbox{ XOR } B is written in base two, the digit in the 2^k's place (k \geq 0) is 1 if either A or B, but not both, has 1 in the 2^k's place, and 0 otherwise.

For example, 3 \mbox{ XOR } 5 = 6. (In base two: 011 \mbox{ XOR } 101 = 110.)

Constraints

2 \leq N \leq 3 \times 10^5

0 \leq A_i < 2^{60}

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_1 A_2 ... A_N

Output

Print the value \sum_{i=1}^{N-1}\sum_{j=i+1}^{N} (A_i \mbox{ XOR } A_j), modulo (10^9+7).

Sample Input 1

3
1 2 3

Sample Output 1

6

We have (1\mbox{ XOR } 2)+(1\mbox{ XOR } 3)+(2\mbox{ XOR } 3)=3+2+1=6.

Sample Input 2

10
3 1 4 1 5 9 2 6 5 3

Sample Output 2

237

Sample Input 3

10
3 14 159 2653 58979 323846 2643383 27950288 419716939 9375105820

Sample Output 3

103715602

Print the sum modulo (10^9+7).

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections.Generic;
//using System.Linq;
using System.Diagnostics;

class Program
{
    static void Main(string[] args)
    {
        const long MOD = 1000000007;
        var sc = new Scanner();
        int n = sc.nextInt();
        var a = new long[n];
        long a_max = 0;
        for (int i = 0; i < n; i++)
        {
            a[i] = sc.nextLong();
            a_max = Math.Max(a_max, a[i]);
        }

        var count = new long[Convert.ToString(a_max, 2).Length];

        for (int i = 0; i < n; i++)
        {
            string a_2 = Convert.ToString(a[i], 2);
            a_2 = a_2.PadLeft(Convert.ToString(a_max, 2).Length, '0');
            for (int j = 0; j < a_2.Length; j++)
            {
                if (a_2[j] == '1') count[j]++;
            }
            Debug.WriteLine("a_2=" + a_2);
        }

        long ans = 0;
        for (int i = 0; i < count.Length; i++)
        {
            long p = 1;
            for (int j = 0; j < count.Length - i - 1; j++)
            {
                p *= 2 % MOD;
            }
            p %= MOD;
            // Debug.WriteLine("i:" + i + "(p)" + p + "*(count)" + count[i] + "*(n-count)" + (n - count[i]));
            long tmp = p * count[i] % MOD;
            ans = ans + tmp * (n - count[i]) % MOD;
            ans %= MOD;
        }
        Console.WriteLine(ans);
    }
}

// chokudai's Scanner
class Scanner
{
    string[] s;
    int i;

    char[] cs = new char[] { ' ' };

    public Scanner()
    {
        s = new string[0];
        i = 0;
    }

    public string next()
    {
        if (i < s.Length) return s[i++];
        string st = Console.ReadLine();
        while (st == "") st = Console.ReadLine();
        s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
        if (s.Length == 0) return next();
        i = 0;
        return s[i++];
    }

    public int nextInt()
    {
        return int.Parse(next());
    }

    public int[] ArrayInt(int N, int add = 0)
    {
        int[] Array = new int[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextInt() + add;
        }
        return Array;
    }

    public long nextLong()
    {
        return long.Parse(next());
    }

    public long[] ArrayLong(int N, long add = 0)
    {
        long[] Array = new long[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextLong() + add;
        }
        return Array;
    }

    public double nextDouble()
    {
        return double.Parse(next());
    }

    public double[] ArrayDouble(int N, double add = 0)
    {
        double[] Array = new double[N];
        for (int i = 0; i < N; i++)
        {
            Array[i] = nextDouble() + add;
        }
        return Array;
    }
}