Python3: solution beats 99.89%
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```\nclass Solution:\n    def findMaxK(self, nums: List[int]) -> int:\n        nums.append(0)\n        nums.sort()\n        coma = nums.index(0)\n        neg = nums[:coma]\n        pos = nums[coma+1:][::-1]\n        neg = set(neg)\n        for i in pos:\n            if -i in neg:\n                return i\n        return -1\n\n```
['Python3']