C# Concise with Linq
csharp\npublic class Solution\n{\n    public int FindMaxK(int[] nums) => nums\n        .Where(int.IsNegative)\n        .Select(int.Abs)\n        .Intersect(nums
```csharp\npublic class Solution\n{\n    public int FindMaxK(int[] nums) => nums\n        .Where(int.IsNegative)\n        .Select(int.Abs)\n        .Intersect(nums.Where(int.IsPositive))\n        .DefaultIfEmpty(-1)\n        .Max();\n}\n```
['Hash Table', 'C#']