AB Balance

2000ms

262144K

Description:

You are given a string $$$s$$$ of length $$$n$$$ consisting of characters a and/or b.

Let $$$\operatorname{AB}(s)$$$ be the number of occurrences of string ab in $$$s$$$ as a substring. Analogically, $$$\operatorname{BA}(s)$$$ is the number of occurrences of ba in $$$s$$$ as a substring.

In one step, you can choose any index $$$i$$$ and replace $$$s_i$$$ with character a or b.

What is the minimum number of steps you need to make to achieve $$$\operatorname{AB}(s) = \operatorname{BA}(s)$$$?

Reminder:

The number of occurrences of string $$$d$$$ in $$$s$$$ as substring is the number of indices $$$i$$$ ($$$1 \le i \le |s| - |d| + 1$$$) such that substring $$$s_i s_{i + 1} \dots s_{i + |d| - 1}$$$ is equal to $$$d$$$. For example, $$$\operatorname{AB}($$$aabbbabaa$$$) = 2$$$ since there are two indices $$$i$$$: $$$i = 2$$$ where aabbbabaa and $$$i = 6$$$ where aabbbabaa.

Input:

Each test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 1000$$$). Description of the test cases follows.

The first and only line of each test case contains a single string $$$s$$$ ($$$1 \le |s| \le 100$$$, where $$$|s|$$$ is the length of the string $$$s$$$), consisting only of characters a and/or b.

Output:

For each test case, print the resulting string $$$s$$$ with $$$\operatorname{AB}(s) = \operatorname{BA}(s)$$$ you'll get making the minimum number of steps.

If there are multiple answers, print any of them.

Sample Input:

4
b
aabbbabaa
abbb
abbaab

Sample Output:

b
aabbbabaa
bbbb
abbaaa

Note:

In the first test case, both $$$\operatorname{AB}(s) = 0$$$ and $$$\operatorname{BA}(s) = 0$$$ (there are no occurrences of ab (ba) in b), so can leave $$$s$$$ untouched.

In the second test case, $$$\operatorname{AB}(s) = 2$$$ and $$$\operatorname{BA}(s) = 2$$$, so you can leave $$$s$$$ untouched.

In the third test case, $$$\operatorname{AB}(s) = 1$$$ and $$$\operatorname{BA}(s) = 0$$$. For example, we can change $$$s_1$$$ to b and make both values zero.

In the fourth test case, $$$\operatorname{AB}(s) = 2$$$ and $$$\operatorname{BA}(s) = 1$$$. For example, we can change $$$s_6$$$ to a and make both values equal to $$$1$$$.

Informação

Provedor Codeforces

Código CF1606A