I don't know how it works but i observed the following pattern: 1, 2, 4, 8 = 120 1, 2, 4, 8, 6(4+2) = 240 1, 2, 4, 10(8+2), 8 = 240 1, 2, 4, 10, 6, 8, 3 = 960 = 120 * BigInteger.Pow(2, arr.count - 4(1 2 4 8 ) //you should use the above examples to solve it rather than look at the code :) //it took me a lot of time and i changed my code several times because i didn't use BigInteger and i was right from the beginning. public static int xoringNinja(List arr) //C# {

    List<int> list = new List<int>();
    int max = 0;
    int i = 1;
    foreach(int x in arr)
    max = (max | x);
    if(max == 0)
    return 0;
    while(max > i)
    {
       i = i << 1;
       if(i == (1 << 30))
       break;
    }
    for(i = i; i != 0; i = i >> 1)
    {
        if((max - i) >= 0)
        {
        list.Add(i);
        max -= i;
        }
    }
    max = 0;
    foreach(int x in list)
    max += x;

    BigInteger b = BigInteger.Multiply(max, BigInteger.Pow(2, list.Count-1));
    if((arr.Count - list.Count) < 1) //0
    {
       for(i = list.Count - arr.Count;i != 0; i--)
       b = b/2;
    }
    else
    {
    b = BigInteger.Multiply(b, BigInteger.Pow(2, arr.Count - list.Count));
    b = b % 1000000007;
    }
    return (int)b;
}