Gap Buffer Insert

Problem

Simulate a gap buffer text editor.

text is the initial text and operations contains ["move", pos] (move the cursor to an absolute position, clamped to both ends), ["insert", s] (insert a string at the cursor and leave the cursor after it), or ["text"] (record the current string).

Return the list of recorded texts (None for move and insert).

Hint

The gap sits between the left and right buffers; moving the cursor slides characters across it.

Test cases

case 1

in: ["abc",[["move",1],["insert","XY"],["text"],["move",0],["insert","z"],["text"]]]

expected: [null,null,"aXYbc",null,null,"zaXYbc"]

case 2

in: ["",[["insert","hi"],["text"]]]

expected: [null,"hi"]

case 3

in: ["ab",[["move",5],["insert","X"],["text"]]]

expected: [null,null,"abX"]

case 4

in: ["ab",[["text"]]]

expected: ["ab"]

Starter codePython

def gap_buffer_ops(text, operations):
    # Your code here
    pass

4 test cases · run your code against them in the editor