Question:

Title: Text Editor with Advanced Undo$/$Redo

Description:

You are tasked with creating a more advanced text editor that supports multiple operations including append, delete, print, undo, and redo. The editor should be capable of reversing previous undo operations through a redo functionality.

The text editor should handle the following operations:

Append a string: Add a string to the end of the current text.

Delete the last k characters: Remove the last k characters from the current text.

Print the ith character: Print the ith character of the current text $(1-$indexed$).$

Undo: Undo the last append or delete operation.

Redo: Redo the last undone operation.

Input Format:

The first line contains an integer n$,$ the number of operations.

The next n lines contain one of the following operations:

$"1"$: Append to the text.

$"2"$: Delete the last k characters from the text.

$"3"$: Print the ith character of the text.

$"4"$: Undo the last operation.

$"5"$: Redo the last undone operation.

Output Format:

For each $"3"$ operation, print the ith character of the current text on a new line.

Constraints:

$1<=$ n $<=10^5$

$1<=|$string$|<=100$

$1<=$ k $<=|$current text$|$

$1<=$ i $<=|$current text$|$

The total length of all append operations will not exceed $10^6$ characters.