Python Elegant & Short | 1 pass
\nfrom sys import maxsize\nfrom typing import List\n\n\nclass Solution:\n    def maximumDifference(self, nums: List[int]) -> int:\n        curr_min = maxsize\n 
```\nfrom sys import maxsize\nfrom typing import List\n\n\nclass Solution:\n    def maximumDifference(self, nums: List[int]) -> int:\n        curr_min = maxsize\n        max_diff = -1\n\n        for num in nums:\n            max_diff = max(max_diff, num - curr_min)\n            curr_min = min(curr_min, num)\n\n        return max_diff or -1\n\n```
['Python', 'Python3']