Design a Text Editor — LeetCode 2296 Python Solution

HardStackDesignLinked ListStringDoubly-Linked ListSimulation
Problem
#2296
Reading time
7 min

The problem

Design a text editor with a cursor that can do the following: Add text to where the cursor is. Delete text from where the cursor is (simulating the backspace key).

Example

Input
["TextEditor", "addText", "deleteText", "addText", "cursorRight", "cursorLeft", "deleteText", "cursorLeft", "cursorRight"]
Output
[null, null, 4, null, "etpractice", "leet", 4, "", "practi"]
Explanation
TextEditor textEditor = new TextEditor(); // The current text is "|". (The '|' character represents the cursor)

Python solution

Python
class TextEditor:
    def __init__(self):
        self.left = []
        self.right = []

    def addText(self, text: str) -> None:
        self.left.extend(list(text))

    def deleteText(self, k: int) -> int:
        k = min(k, len(self.left))
        for _ in range(k):
            self.left.pop()
        return k

    def cursorLeft(self, k: int) -> str:
        k = min(k, len(self.left))
        for _ in range(k):
            self.right.append(self.left.pop())
        return ''.join(self.left[-10:])

    def cursorRight(self, k: int) -> str:
        k = min(k, len(self.right))
        for _ in range(k):
            self.left.append(self.right.pop())
        return ''.join(self.left[-10:])


# Your TextEditor object will be instantiated and called as such:
# obj = TextEditor()
# obj.addText(text)
# param_2 = obj.deleteText(k)
# param_3 = obj.cursorLeft(k)
# param_4 = obj.cursorRight(k)

Complexity

MeasureComplexity
TimeO(|\text{text}|)
SpaceO(n) auxiliary

Pattern: Linked List

Rewire pointers in place, with a dummy head and a saved next to keep it safe. LeetCode 2296. Design a Text Editor is filed here because LeetCode tags it Linked List and Doubly-Linked List, which is the vocabulary this hub collects.

The linked list guide has the Python template for the pattern and the 75 LeetCode problems that use it.

Related problems

Frequently asked questions

How hard is LeetCode 2296. Design a Text Editor?
LeetCode 2296. Design a Text Editor is rated Hard on LeetCode.
What is the time complexity of LeetCode 2296. Design a Text Editor?
The Python solution on this page runs in O(|\text{text}|).
What is the space complexity of LeetCode 2296. Design a Text Editor?
The Python solution on this page uses O(n) auxiliary space.
What topics does LeetCode 2296. Design a Text Editor cover?
LeetCode 2296. Design a Text Editor is tagged Stack, Design, Linked List, String, Doubly-Linked List and Simulation on LeetCode.

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