Leetcode 2016. Maximum Difference Between Increasing Elements

class Solution:
    def maximumDifference(self, nums: List[int]) -> int:
        length = len(nums)
        diff = -1
        for i in range(length):
            for j in range(i+1, length):
                if nums[j] > nums[i]:
                    diff = max(diff, nums[j] - nums[i])
        return diff

class Solution:
    def maximumDifference(self, nums: List[int]) -> int:
        length = len(nums)
        diff = -1
        minimum = nums[0]
        for num in nums:
            if num > minimum:
                diff = max(diff, num - minimum)
            minimum = min(minimum, num)
        return diff