C# 代码
public class Solution {
public int CountWays(IList<int> nums) {
int n = nums.Count;
nums = nums.OrderBy(num => num).ToList();
int result = nums[0] == 0 ? 1 : 2;
for (int i = 0; i < n - 1; i++){
if (nums[i] < i + 1 && nums[i + 1] > i + 1) result++;
}
return result;
}
}