Minimum Insertion Steps to Make a String Palindrome LeetCode solution in Python

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class Solution:
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    def minInsertions(self, s: str) -> int:
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        n = len(s)
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        prev_prev = [0] * n
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        prev = [0] * n
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        curr = [0] * n
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        for l in range(1, n):
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            for i in range(l, n):
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                if s[i] == s[i - l]:
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                    curr[i] = prev_prev[i - 1]
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                else:
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                    curr[i] = min(prev[i - 1], prev[i]) + 1
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            # print(curr)
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            prev_prev, prev, curr = prev, curr, prev_prev
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        return prev[-1]