Codeforces Round 557 (Div. 2) [based on Forethought Future Cup - Final Round]
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You are given a string $s$ consisting of characters "1", "0", and "?". The first character of $s$ is guaranteed to be "1". Let $m$ be the number of characters in $s$.
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Count the number of ways we can choose a pair of integers $a, b$ that satisfies the following:
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$1 \leq a \lt b \lt 2^m$- When written without leading zeros, the base-2 representations of
$a$and$b$are both palindromes. - The base-2 representation of
bitwise XORof$a$and$b$matches the pattern$s$. We say that$t$matches$s$if the lengths of$t$and$s$are the same and for every$i$, the$i$-th character of$t$is equal to the$i$-th character of$s$, or the$i$-th character of$s$is "?".
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Compute this count modulo $998244353$.
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Input
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The first line contains a single string $s$ ($1 \leq |s| \leq 1\,000$). $s$ consists only of characters "1", "0" and "?". It is guaranteed that the first character of $s$ is a "1".
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Output
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Print a single integer, the count of pairs that satisfy the conditions modulo $998244353$.
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Note
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For the first example, the pairs in base-2 are $(111, 10001), (11, 10101), (1001, 11111)$.
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样例
Input #1
10110
Output #1
3
InputCopy
OutputCopy
Input #2
1?0???10
Output #2
44
InputCopy
OutputCopy
Input #3
1?????????????????????????????????????
Output #3
519569202
InputCopy
OutputCopy
Input #4
1
Output #4
0
InputCopy
OutputCopy
题目信息
题号
1162F
时间限制
1 s
内存限制
256 MB
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