public override IEnumerable <object> Solve(TextReader inputStream)
{
Modular.InitializeCombinationTable();
var n = inputStream.ReadInt();
var a = inputStream.ReadIntArray();
var diffs = new Modular[a.Length - 1];
for (int i = 0; i < diffs.Length; i++)
{
diffs[i] = new Modular(Math.Abs(a[i] - a[i + 1]));
}
var result = Modular.GetZero();
for (int i = 0; i < diffs.Length; i++)
{
result += diffs[i] * Modular.Combination(diffs.Length - 1, i);
}
yield return(result);
}
