First Unique Character in a Stream Problem Statement

Given a string A consisting of lowercase English letters, determine the first non-repeating character at each point in the stream of characters.

Example:

Input:

bbaca

Output:

baaac

Explanation:

For the given string 'bbaca':
1. First stream is 'b'; first non-repeating character is 'b'.
2. Next stream is 'bb'; no non-repeating character.
3. Next stream is 'bba'; first non-repeating character is 'a'.
4. Next stream is 'bbac'; first non-repeating character is 'a'.
5. Next stream is 'bbaca'; first non-repeating character is 'c'.

Constraints:

• 1 <= T <= 100
• 1 <= N <= 10000

Input:

The first line contains an integer 'T', the number of test cases.
 Each of the next 'T' lines contains a string 'A'.

Output:

For each test case, print a string of characters that represent the first non-repeating character at each point in the stream.

Note: You do not need to print anything; it is handled externally.