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# Runtime: 173 ms (Top 90.14%) | Memory: 14.9 MB (Top 69.01%)
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class Solution:
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    def sumGame(self, num: str) -> bool:
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        n = len(num)
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        q_cnt_1 = s1 = 0
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        for i in range(
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            n // 2
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        ):  # get digit sum and question mark count for the first half of `num`
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            if num[i] == "?":
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                q_cnt_1 += 1
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            else:
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                s1 += int(num[i])
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        q_cnt_2 = s2 = 0
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        for i in range(
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            n // 2, n
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        ):  # get digit sum and question mark count for the second half of `num`
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            if num[i] == "?":
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                q_cnt_2 += 1
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            else:
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                s2 += int(num[i])
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        s_diff = s1 - s2  # calculate sum difference and question mark difference
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        q_diff = q_cnt_2 - q_cnt_1
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        return not (
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            q_diff % 2 == 0 and q_diff // 2 * 9 == s_diff
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        )  # When Bob can't win, Alice wins