Implement a Cursor-Based Text Editor

Problem Statement

Design a text editor that maintains a text string and a cursor position. The editor starts empty with the cursor at position 0 (the very beginning of the document).

Implement the TextEditor class:

• TextEditor(): Initializes the text editor with an empty text.
• insert(text: str) -> None: Inserts text at the current cursor position. The cursor moves to the right of the newly inserted characters.
• delete(k: int) -> int: Deletes up to k characters immediately to the left of the cursor. The cursor shifts left by the number of deleted characters. Returns the actual number of characters deleted.
• cursor_left(k: int) -> str: Moves the cursor k positions to the left (stopping at index 0 if it reaches the start of the text). Returns the last min(10, len) characters immediately to the left of the cursor (where len is the number of characters to the left of the cursor).
• cursor_right(k: int) -> str: Moves the cursor k positions to the right (stopping at the end of the text if it reaches the end). Returns the last min(10, len) characters immediately to the left of the cursor.

Example

editor = TextEditor()
editor.insert("hello")        # Text: "hello|", cursor is after 'o'
editor.delete(2)              # Deletes 'l' and 'o', returns 2. Text: "hel|"
editor.insert("p")          # Text: "help|"
editor.cursor_left(2)         # Moves cursor 2 left: "he|lp", returns "he"
editor.cursor_right(1)        # Moves cursor 1 right: "hel|p", returns "hel"
editor.delete(10)             # Attempts to delete 10 left of cursor, deletes 3 ('h', 'e', 'l'), returns 3. Text: "|p"

Constraints

• 1 <= len(text) <= 40 per insert call
• 1 <= k <= 40 per delete, cursor_left, and cursor_right call
• text consists only of lowercase English letters.
• At most 2 * 10^5 calls will be made in total across all methods.
• Operations must run efficiently enough to handle heavy sequences of insertions, moves, and deletions without quadratic time degradation.