The Boston Consulting Group, Inc. Data Engineer Interview Guide

The The Boston Consulting Group, Inc. data engineer loop, round by round: what each stage tests, example questions with the guidance interviewers actually score, the mistakes that sink strong candidates, and how to prepare.

Last updated: Proudly published by: Jeff Wahl

What the The Boston Consulting Group, Inc. loop tests: domains and difficulty

Our prediction of the question mix by domain and difficulty for this company's data engineer loop, from live listings and interview reports.

By domain
SQL
38%
5
Python
62%
8
By difficulty
Easy
54%
7
Medium
23%
3
Hard
23%
3

The domain and difficulty mix we predict for a The Boston Consulting Group, Inc. data engineer loop, across 13 problems. It updates as more The Boston Consulting Group, Inc. data lands.

Updated 13 predicted The Boston Consulting Group, Inc. problems

8 real The Boston Consulting Group, Inc. interview questions

Reported by candidates from real loops, tagged by domain, round, level, and year. Expand for what the round is scoring.

PythonL5 · 2026
the exercise was given a list and a target number what are the indexes that there some equals the target number
Online assessment
+
PythonL5 · 2026
basic DSA like bubble sort anagram
Phone screen · screen python
+
PythonL5 · 2026
the exercise was given a list and a target number what are the indexes that there some equals the target number
Online assessment
+
PythonL5 · 2026
basic DSA like bubble sort anagram
Phone screen · screen sql
+
PythonL5 · 2025
Asked oops related coding questions in Java/Python
Online assessment
+
Pythonunknown · 2024
Implement a Stack class in Python using a List as the underlying data structure, with push and pop methods.
Onsite · python
+

Round 1 of the onsite interview at BCG X. Required: implement a Stack class in Python using a List as the underlying data structure, with push and pop methods.

PythonL5 · 2024
Implement a Queue class using two lists as stacks, with enqueue and dequeue methods
Onsite · python
+

Implement a class MyQueue that uses only two Python lists (acting as stacks, using only append() and pop()) to provide queue behavior (FIFO). Implement enqueue(value) and dequeue() methods. dequeue() should raise an IndexError if the queue is empty. Example: q = MyQueue() q.enqueue(1) q.enqueue(2) q.enqueue(3) q.dequeue() -> 1 q.dequeue() -> 2 q.enqueue(4) q.dequeue() -> 3 q.dequeue() -> 4 q.dequeue() -> raises IndexError Edge cases: dequeue on empty queue, interleaved enqueue/dequeue operations, single element enqueue then dequeue.

Pythonunknown · 2024
Given an array, find the longest subsequence whose sum is maximum.
Onsite · python
+

Round 3 in-person interview at BCG X. Python required. Find the longest subsequence in an array whose sum is maximum. No further constraints described.

How candidates rate the The Boston Consulting Group, Inc. loop

How hard candidates rated the loop and how they felt, summarized across the reports below.

How hard candidates rated it
Easy
13%
Medium
63%
Hard
25%

8 rated reports

How candidates felt
Positive
43%
Neutral
29%
Negative
29%

7 rated The Boston Consulting Group, Inc. reports

Try a The Boston Consulting Group, Inc.-style SQL round

Find every user active on 3 or more CONSECUTIVE days. This gaps-and-islands shape shows up in nearly every DE SQL round. Edit the query and run it against the seed data.

/* Users active on 3+ consecutive days. */
/* Hint: date minus a per-user ROW_NUMBER is constant within a streak. */
WITH streaks AS (
SELECT
user_id,
activity_date,
activity_date - CAST(
(ROW_NUMBER() OVER (
PARTITION BY user_id
ORDER BY activity_date
))
AS INT
) AS grp
FROM user_sessions
)
SELECT
user_id
FROM streaks
GROUP BY user_id, grp
HAVING COUNT(*) >= 3

Practice the The Boston Consulting Group, Inc. loop

The problems our model expects in this company's interview, grouped by round. Work the shapes that come up, not the ones that read well on a list.

The Boston Consulting Group, Inc. compensation and culture

The numbers, tech stack, and team structure live on the company overview.

Compare The Boston Consulting Group, Inc. with other data engineering employers

How the role, pay, and loop stack up against peer companies.

02 / Why practice

Prepare at The Boston Consulting Group, Inc. interview difficulty

  1. 01

    Reading a solution is not the same as writing one

    Every engineer who has frozen on a query they had read a dozen times knows the gap. The only preparation that closes it is producing the answer yourself, under time, before the interview does it for you

  2. 02

    76% of hiring managers reject on the coding task, not the resume

    From HackerRank's 2024 Developer Skills Report. Candidates who look strong on paper still fail the live screen if they haven't done timed, executable practice

  3. 03

    5 problem shapes cover 80% of data engineer loops

    Dedup, sessionization, top-N-per-group, slowly-changing dimensions, partition tricks. Writing the shapes by hand turns the unfamiliar into pattern recognition

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