题目描述
You are given strings $S$ and $T$, consisting of lowercase English letters. It is guaranteed that $T$ is a permutation of the string abc.
Find string $S'$, the lexicographically smallest permutation of $S$ such that $T$ is not a subsequence of $S'$.
String $a$ is a permutation of string $b$ if the number of occurrences of each distinct character is the same in both strings.
A string $a$ is a subsequence of a string $b$ if $a$ can be obtained from $b$ by deletion of several (possibly, zero or all) elements.
A string $a$ is lexicographically smaller than a string $b$ if and only if one of the following holds:
- $a$ is a prefix of $b$, but $a \ne b$;
- in the first position where $a$ and $b$ differ, the string $a$ has a letter that appears earlier in the alphabet than the corresponding letter in $b$.
Input
Each test contains multiple test cases. The first line contains a single integer $t$ ($1 \le t \le 1000$) — the number of test cases. Description of the test cases follows.
The first line of each test case contains a string $S$ ($1 \le |S| \le 100$), consisting of lowercase English letters.
The second line of each test case contains a string $T$ that is a permutation of the string abc. (Hence, $|T| = 3$).
Note that there is no limit on the sum of $|S|$ across all test cases.
Output
For each test case, output a single string $S'$, the lexicographically smallest permutation of $S$ such that $T$ is not a subsequence of $S'$.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
样例输出
提示
In the first test case, both aaaabbc and aaaabcb are lexicographically smaller than aaaacbb, but they contain abc as a subsequence.
In the second test case, abccc is the smallest permutation of cccba and does not contain acb as a subsequence.
In the third test case, bcdis is the smallest permutation of dbsic and does not contain bac as a subsequence.