在对数组进行排序时将数字插入数组的更好方法

Question

Let's say I want to insert values into an array while at the same time sorting it. This was my solution:

int[] arr = new int[5];
int  k;
arr[0] = int.Parse(Console.ReadLine());

for (int i = 1; i < arr.Length; i++)
{
    int num = int.Parse(Console.ReadLine());

    for (k = i; k > 0 && num < arr[k - 1];--k) arr[k] = arr[k - 1];

    arr[k] = num;
}

I know I didn't handle exceptions, I'm just talking about the code itself.

Is there a better way of doing this?

Answer 1

You can use a SortedSet<> , that gets automatically sorted as you add items.

var numbers = new SortedSet<int>()
{
    4,
    9,
    6,
    3
};

foreach (var number in numbers)
{
    Console.WriteLine(number);
}

Answer 2

If it doesn't have to be array you could do this:

static void Main(string[] args)
{
 List<int> list = new List<int>
  {
    1,
    2,
    7,
    10
  };

  int k = int.Parse(Console.ReadLine());
  list.Add(k);
  list.Sort();
}

Edit: if you want to sort when inserting you could do this:

 int k = int.Parse(Console.ReadLine());
  int i = list.Where(x => x > k).Min();
  int index = list.IndexOf(i);
  list.Insert(index, k);

Answer 3

You can use a List and convert it into an array. When you maintain your list ordered at all time you can use the list's BinarySearch method to get the insert index:

const int length = 5;

List<int> result = new List<int>(length);

for (int i = 0; i < length; i++) {
    int num = int.Parse(Console.ReadLine());
    int insertIndex = result.BinarySearch(num);
    if (insertIndex < 0) {
        insertIndex = ~insertIndex;
    }
    result.Insert(insertIndex, num);
}
int[] arr = result.ToArray();

The binary search is much faster than the linear search you are currently performing. You won't see that with your current 5 values. You would defenitely see it with larger lists (hundrets or thousands of values).