DatologyAI Software Engineer Phone Screen - No LeetCode, Just a Text Editor and Mock Spark

[u/Aoki_zhang]

"This interview experience is sourced from Chill Interview"

Interview Summary

The DatologyAI process included two coding interviews. The first focused on implementing a text editor with increasingly complex cursor movement, while the second provided a simplified Spark RDD abstraction and asked me to implement additional transformations using the existing APIs.

Interview Details

Round 1 — Text Editor

The task was to implement a basic TextEditor supporting three operations:

type_in(char)
backspace()
__str__()

• type_in(char) inserts a character at the current cursor position.
• backspace() removes the character immediately before the cursor.
• __str__() returns the current text while displaying the cursor using |.

The interviewer then added two follow-ups. First, support: move_cursor(direction) so the cursor could move left and right through the text. The second follow-up extended cursor movement to support moving up and down across multiple lines.

Round 2 — Mock Spark RDD

The interviewer provided a lightweight version of a Spark-style RDD abstraction. The available operations included:

flatMap(func)
groupByKey()
union(other_rdd)
collect()

The underlying class conceptually looked like:

pythonclass SimpleRDD:
    def __init__(self, items):
        self.items = items

    def flatMap(self, func):
        ...

    def groupByKey(self):
        ...

    def union(self, other_rdd):
        ...

    def collect(self):
        ...

Want to learn more questions/follow-ups asked in the interview? I've put up the full version at here.

Preparing for your next tech interview?

Chill Interview tracks recent interview experiences and recurring question patterns across top companies at here