Best Time to Buy and Sell Stock with Transaction Fee LeetCode solution in Python

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class Solution:
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    def maxProfit(self, prices: List[int], fee: int) -> int:
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        n = len(prices)
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        lookup = {}
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        def f(ind, buy, lookup):
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            if ind == n:
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                return 0
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            if (ind, buy) in lookup:
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                return lookup[(ind, buy)]
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            profit = 0
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            if buy:
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                profit = max(
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                    -prices[ind] + f(ind + 1, 0, lookup), f(ind + 1, 1, lookup)
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                )
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            else:
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                profit = max(
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                    prices[ind] + f(ind + 1, 1, lookup) - fee, f(ind + 1, 0, lookup)
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                )
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            lookup[(ind, buy)] = profit
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            return lookup[(ind, buy)]
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        return f(0, 1, lookup)