Codeforces Round 715 (Div. 2)
D
Binary Literature
Codeforces
未评级
原题
← CE →
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A bitstring is a string that contains only the characters 0 and 1.

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Koyomi Kanou is working hard towards her dream of becoming a writer. To practice, she decided to participate in the Binary Novel Writing Contest. The writing prompt for the contest consists of three bitstrings of length $2n$. A valid novel for the contest is a bitstring of length at most $3n$ that contains at least two of the three given strings as subsequences.

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Koyomi has just received the three prompt strings from the contest organizers. Help her write a valid novel for the contest.

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A string $a$ is a subsequence of a string $b$ if $a$ can be obtained from $b$ by deletion of several (possibly, zero) characters.

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Input

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The first line contains a single integer $t$ ($1 \le t \le 10^4$) — the number of test cases.

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The first line of each test case contains a single integer $n$ ($1 \le n \le 10^5$).

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Each of the following three lines contains a bitstring of length $2n$. It is guaranteed that these three strings are pairwise distinct.

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It is guaranteed that the sum of $n$ across all test cases does not exceed $10^5$.

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Output

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For each test case, print a single line containing a bitstring of length at most $3n$ that has at least two of the given bitstrings as subsequences.

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It can be proven that under the constraints of the problem, such a bitstring always exists.

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If there are multiple possible answers, you may output any of them.

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Note

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In the first test case, the bitstrings 00 and 01 are subsequences of the output string: 010 and 010. Note that 11 is not a subsequence of the output string, but this is not required.

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In the second test case all three input strings are subsequences of the output string: 011001010, 011001010 and 011001010.

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样例

Input #1
2
1
00
11
01
3
011001
111010
010001
Output #1
010
011001010
InputCopy OutputCopy
题目信息
题号
1509D
时间限制
1 s
内存限制
256 MB

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。