1def special_array(nums):
2    nums.sort()
3    for x in range(len(nums) + 1):
4        count = sum(1 for num in nums if num >= x)
5        if count == x:
6            return x
7    return -1
8
9nums = [0, 4, 3, 0, 4]
10print(special_array(nums))

1using System.Linq;

class SpecialArray {
    private int CountGreaterEqual(int[] nums, int target) {
        return nums.Count(num => num >= target);
    }

    public int SpecialArrayFunc(int[] nums) {
        Array.Sort(nums);
        int left = 0, right = nums.Length;
        while (left <= right) {
            int mid = left + (right - left) / 2;
            int count = CountGreaterEqual(nums, mid);
            if (count == mid) {
                return mid;
            } else if (count < mid) {
                right = mid - 1;
            } else {
                left = mid + 1;
            }
        }
        return -1;
    }

    static void Main() {
        SpecialArray sa = new SpecialArray();
        int[] nums = {0, 4, 3, 0, 4};
        Console.WriteLine(sa.SpecialArrayFunc(nums));
    }
}