Здравейте, имам проблем със задача 08. Simple Text Editor от Java Advanced
08.*Simple Text Editor
You are given an empty text. Your task is to implement 4 types of commands related to manipulating the text:
- "1 [string]" - appends [string] to the end of the text
- "2 [count]" - erases the last [count] elements from the text
- "3 [index]" - returns the element at position [index] from the text
- "4" - undoes the last not-undone command of type 1 or 2 and returns the text to the state before that operation
- The first line contains N, the number of operations, where 1 ≤ N ≤ 105
- Each of the following N lines contains the name of the operation, followed by the command argument, if any, separated by space in the following format "command argument".
- The length of the text will not exceed 1000000
- All input characters are English letters
- It is guaranteed that the sequence of input operation is possible to perform
- For each operation of type "3" print a single line with the returned character of that operation.
There are 8 operations. Initially, the text is empty.
Print third character
Erase 3 characters
Print second character
Undo last command - text is now ""
Undo last command - text is now "abc"
Print first character
тестовата задача е ок, но ми дава 7 runtime error - a.
Това ми е кодът. Дали може някой да каже къде е проблемът?