Longest Turbulent Subarray LeetCode solution in Python

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# Runtime: 1152 ms (Top 13.10%) | Memory: 18.7 MB (Top 31.75%)
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class Solution:
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    def maxTurbulenceSize(self, arr: List[int]) -> int:
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        def cmp(a, b):
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            if a == b:
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                return 0
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            if a > b:
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                return 1
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            return -1
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        n = len(arr)
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        ans = 1
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        prev = 0
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        for i in range(1, n):
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            c = cmp(arr[i - 1], arr[i])
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            if c == 0:
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                # we shift prev to i
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                prev = i
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            elif i == n - 1 or c * cmp(arr[i], arr[i + 1]) != -1:
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                ans = ans if ans > i - prev + 1 else i - prev + 1
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                prev = i
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        return ans