String Transformation Problem

Given a string (STR) of length N, you are tasked to create a new string through the following method:

Select the smallest character from the first K characters of STR, remove it from STR, and append it to the new string. Continue this operation until STR becomes empty.

Input:

The first line contains an integer 'T', the number of test cases. Each subsequent line for a test case contains a string (STR) followed by an integer (K) separated by a space.

Output:

For each test case, output the newly formed string after performing the operations. Print each result on a new line.

Example:

Input:

edcba 4

Output:

bacde

Explanation:

For STR = "edcba" and K = 4:
- Initial new string is empty, newString = "".
- First set of characters: ('e', 'd', 'c', 'b'), smallest is 'b', so newString = "b".
- Next set after removal: ('e', 'd', 'c', 'a'), smallest is 'a', so newString = "ba".
- Remaining 'edc', which is appended in sorted order, resulting in newString = "bacde".

Constraints:

• 1 ≤ T ≤ 100
• 0 ≤ N ≤ 105
• 1 ≤ K ≤ 105

Note that the time limit for processing all test cases is 1 second.