CF2248A.You Delete, I Delete

Alice and Bob are given a binary string$^{\text{∗}}$ $s$ of length $n$. It contains at least one $\mathtt{0}$ and at least one $\mathtt{1}$.

They each perform exactly one operation in the following order:

• First, Alice chooses an occurrence of $\mathtt{0}$ in $s$ and deletes it.
• Then, Bob chooses an occurrence of $\mathtt{1}$ in the resulting string and deletes it.

Alice wants the final string to be lexicographically$^{\text{†}}$ as large as possible, while Bob wants it to be lexicographically as small as possible. Determine the final string if both players act optimally.

$^{\text{∗}}$A binary string is a string consisting only of the characters $\mathtt{0}$ and $\mathtt{1}$.

$^{\text{†}}$For two distinct binary strings $a$ and $b$ of the same length, $a$ is lexicographically smaller than $b$ if, at the first position where they differ, $a$ has the smaller digit.

Alice 和 Bob 得到一个长度为 $n$ 的二进制字符串$^{\text{∗}}$ $s$。该字符串中至少包含一个 $\mathtt{0}$ 和一个 $\mathtt{1}$。

他们各自恰好执行一次操作，顺序如下：

• 首先，Alice 在 $s$ 中选择一个 $\mathtt{0}$ 并将其删除；
• 然后，Bob 在删除后的字符串中选择一个 $\mathtt{1}$ 并将其删除。

Alice 希望最终字符串的字典序$^{\text{†}}$尽可能大，而 Bob 希望其字典序尽可能小。若双方均采取最优策略，求最终字符串。

$^{\text{∗}}$二进制字符串是指仅由字符 $\mathtt{0}$ 和 $\mathtt{1}$ 组成的字符串。

$^{\text{†}}$对于两个长度相同且互不相同的二进制字符串 $a$ 和 $b$，若在它们首次出现差异的位置上，$a$ 的数字更小，则称 $a$ 的字典序小于 $b$。

Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 100$). The description of the test cases follows.

The only line of each test case contains a binary string $s$ of length $n$ ($3 \le n \le 100$).

It is guaranteed that $s$ contains at least one $\mathtt{0}$ and at least one $\mathtt{1}$.

每个测试包含多个测试用例。第一行包含测试用例的数量 $t$（$1 \le t \le 100$）。随后是测试用例的描述。

每个测试用例仅有一行，包含一个长度为 $n$ 的二进制字符串 $s$（$3 \le n \le 100$）。

保证 $s$ 中至少包含一个 $\mathtt{0}$ 和至少一个 $\mathtt{1}$。

For each test case, output the final string if both players act optimally.

对于每个测试用例，若双方玩家均采取最优策略，则输出最终的字符串。

In the first test case, Alice must delete the only $\mathtt{0}$. Bob may delete either occurrence of $\mathtt{1}$, so the resulting string is $\mathtt{1}$.

In the second test case, Alice may delete either occurrence of $\mathtt{0}$. Bob optimally deletes one of the first two occurrences of $\mathtt{1}$, so the resulting string is $\mathtt{101}$.

In the third test case, Alice may delete any occurrence of $\mathtt{0}$. Bob then deletes the only occurrence of $\mathtt{1}$, so the resulting string is $\mathtt{00}$.

在第一个测试用例中，Alice 必须删除唯一的 $\mathtt{0}$。Bob 可以删除任意一个 $\mathtt{1}$，因此最终字符串为 $\mathtt{1}$。

在第二个测试用例中，Alice 可以删除任意一个 $\mathtt{0}$。Bob 最优地删除前两个 $\mathtt{1}$ 中的任意一个，因此最终字符串为 $\mathtt{101}$。

在第三个测试用例中，Alice 可以删除任意一个 $\mathtt{0}$。随后 Bob 删除唯一的 $\mathtt{1}$，因此最终字符串为 $\mathtt{00}$。