6. 共享停車位

Stack<int> outTime = new Stack<int>();
string k;
while ((k = Console.ReadLine()) != "")
{
    var data = k.Split(' ');
    var tin = int.Parse(data[0]);
    var tout = int.Parse(data[1]);
    if (outTime.Count == 0 || tin >= outTime.Peek() || outTime.Peek() >= tout)
    {
        outTime.Push(tout);
    }
}
Console.WriteLine(outTime.Count);