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class Solution:
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    def threeEqualParts(self, arr: List[int]) -> List[int]:
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        n = len(arr)
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        count_one = arr.count(1)
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        if count_one == 0:
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            return [0, n - 1]
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        if count_one % 3 != 0:
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            return [-1, -1]
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        target_ones = count_one // 3
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        breaks = []
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        one_count = 0
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        for i, bit in enumerate(arr):
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            if bit == 1:
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                one_count += 1
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                if one_count in [1, target_ones + 1, 2 * target_ones + 1]:
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                    breaks.append(i)
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                if one_count in [target_ones, 2 * target_ones, 3 * target_ones]:
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                    breaks.append(i)
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        i1, j1, i2, j2, i3, j3 = breaks
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        if not arr[i1 : j1 + 1] == arr[i2 : j2 + 1] == arr[i3 : j3 + 1]:
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            return [-1, -1]
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        trailing_zeroes_left = i2 - j1 - 1
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        trailing_zeroes_mid = i3 - j2 - 1
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        trailing_zeroes_right = n - j3 - 1
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        if trailing_zeroes_right > min(trailing_zeroes_left, trailing_zeroes_mid):
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            return [-1, -1]
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        j1 += trailing_zeroes_right
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        j2 += trailing_zeroes_right
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        return [j1, j2 + 1]