How can I manipulate an array to make the largest number?

Question

Say you have an array of positive integers, manipulate them so that the concatenation of the integers of the resultant array is the largest number possible. Ex: {9,1,95,17,5}, r

Answer 1

In C#

static void Concat(params int[] array)
{
    List values = new List(array);
    values.Sort((a, b) =>
        {
            StringBuilder asb = new StringBuilder(a.ToString());
            StringBuilder bsb = new StringBuilder(b.ToString());

            int lengthDiff = asb.Length - bsb.Length;

            if (lengthDiff == 0)
                return -a.CompareTo(b);
            else if (lengthDiff > 0)
                bsb.Append(bsb[bsb.Length - 1], lengthDiff);
            else
                asb.Append(asb[asb.Length - 1], -lengthDiff);

            return -asb.ToString().CompareTo(bsb.ToString());
        });

If you're familier with sign-extending bits, you can see this does exactly that only in reverse. It extends the shorter length number's last digit out to the same length and them simply returns the string comparison.