Minimum Number of K Consecutive Bit Flips LeetCode solution in Python

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# Runtime: 2365 ms (Top 19.91%) | Memory: 17.1 MB (Top 67.10%)
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class Solution:
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    def minKBitFlips(self, nums: List[int], k: int) -> int:
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        flips = [0] * len(nums)
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        csum = 0
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        for left in range(0, len(nums) - k + 1):
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            if (nums[left] + csum) % 2 == 0:
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                flips[left] += 1
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                csum += 1
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            if left >= k - 1:
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                csum -= flips[left - k + 1]
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        for check in range(len(nums) - k + 1, len(nums)):
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            if (nums[check] + csum) % 2 == 0:
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                return -1
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            if check >= k - 1:
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                csum -= flips[check - k + 1]
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        return sum(flips)