Decrease Elements To Make Array Zigzag LeetCode solution in Python

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class Solution:
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    def solve(self, arr, n, x):
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        idx = 1
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        ans = 0
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        while idx < n:
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            if idx == 0:
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                idx += 1
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            if idx % 2 == x:
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                if arr[idx - 1] >= arr[idx]:
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                    ans += arr[idx - 1] - arr[idx] + 1
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                    arr[idx - 1] = arr[idx] - 1
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                    idx = idx - 1
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                else:
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                    idx = idx + 1
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            else:
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                if arr[idx - 1] <= arr[idx]:
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                    ans += arr[idx] - arr[idx - 1] + 1
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                    arr[idx] = arr[idx - 1] - 1
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                idx += 1
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        return ans
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    def movesToMakeZigzag(self, nums: List[int]) -> int:
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        ans1 = self.solve([x for x in nums], len(nums), 0)
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        ans2 = self.solve([x for x in nums], len(nums), 1)
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        return min(ans1, ans2)