How do I approach Coding & Algorithms interview questions?

Coding & Algorithms questions require understanding of core concepts and practice. PracHub provides solutions with explanations to help you master coding & algorithms interviews.

What difficulty level is this interview question?

This is a medium difficulty Coding & Algorithms question, commonly asked during Take-home Project rounds at Booking.

What role is this question designed for?

This question is commonly asked for Software Engineer candidates at Booking during technical interviews.

Solve three OA coding questions | Booking Interview Question

Q: Solve three OA coding questions

This 90-minute assessment evaluates algorithmic problem-solving skills including string manipulation and grouping for anagram detection, digit-level reasoning for one-swap maximization, and text tokenization with aggregation and ranking for sentiment-based scoring.

You are given a 90-minute online assessment containing three coding questions. Implement solutions for all questions.

Question 1: Group strings that are anagrams

Given an array of strings strs, group the strings into lists where each list contains strings that are anagrams of each other.

Input

strs : array of lowercase strings (may include duplicates)

Output

A list of groups (each group is a list of strings). Order of groups and order within a group do not matter.

Constraints (typical)

1 <= len(strs) <= 10^4
0 <= len(strs[i]) <= 100

Question 2: Maximize an integer by swapping two digits at most once

Given a non-negative integer num, you may swap at most one pair of its digits (or perform no swap). Return the maximum value you can obtain.

Input

num : non-negative integer

Output

Maximum integer achievable after at most one swap

Constraints (typical)

0 <= num <= 10^8

Question 3: Rank hotels by review sentiment and return top-k

You are given:

A set of positive keywords and negative keywords .
A list of hotel reviews, each associated with a hotel_id .
An integer k .

Compute each hotel’s total sentiment score by scanning all its reviews.

Scoring rules

Tokenize each review into words by splitting on non-letter characters (punctuation and symbols are separators).
Comparison is case-insensitive .
For every word occurrence:
- If the word is in the positive set: +1
- If the word is in the negative set: -1
- Otherwise: 0
A hotel’s total score is the sum across all its reviews.

Task

Return the top k hotel IDs ranked by:

Higher total score first
If tied, smaller hotel_id first

Input (one reasonable spec)

positive_keywords : string or list of words
negative_keywords : string or list of words
hotel_ids : array of integers, parallel to reviews
reviews : array of strings
k : integer

Output

Array of k hotel IDs in sorted ranking order

Constraints (typical)

1 <= len(reviews) == len(hotel_ids) <= 10^5
Total review text length up to ~ 10^6
1 <= k <= number_of_distinct_hotels

Notes

If a hotel has multiple reviews, aggregate them.
If there are fewer than k hotels (in some variants), return all hotels sorted by the same rule.

You are given a 90-minute online assessment containing three coding questions. Implement solutions for all questions.

Question 1: Group strings that are anagrams

Given an array of strings strs, group the strings into lists where each list contains strings that are anagrams of each other.

Input

strs : array of lowercase strings (may include duplicates)

Output

A list of groups (each group is a list of strings). Order of groups and order within a group do not matter.

Constraints (typical)

1 <= len(strs) <= 10^4
0 <= len(strs[i]) <= 100

Question 2: Maximize an integer by swapping two digits at most once

Given a non-negative integer num, you may swap at most one pair of its digits (or perform no swap). Return the maximum value you can obtain.

Input

num : non-negative integer

Output

Maximum integer achievable after at most one swap

Constraints (typical)

0 <= num <= 10^8

Question 3: Rank hotels by review sentiment and return top-k

You are given:

A set of positive keywords and negative keywords .
A list of hotel reviews, each associated with a hotel_id .
An integer k .

Compute each hotel’s total sentiment score by scanning all its reviews.

Scoring rules

Tokenize each review into words by splitting on non-letter characters (punctuation and symbols are separators).
Comparison is case-insensitive .
For every word occurrence:
- If the word is in the positive set: +1
- If the word is in the negative set: -1
- Otherwise: 0
A hotel’s total score is the sum across all its reviews.

Task

Return the top k hotel IDs ranked by:

Higher total score first
If tied, smaller hotel_id first

Input (one reasonable spec)

positive_keywords : string or list of words
negative_keywords : string or list of words
hotel_ids : array of integers, parallel to reviews
reviews : array of strings
k : integer

Output

Array of k hotel IDs in sorted ranking order

Constraints (typical)

1 <= len(reviews) == len(hotel_ids) <= 10^5
Total review text length up to ~ 10^6
1 <= k <= number_of_distinct_hotels

Notes

If a hotel has multiple reviews, aggregate them.
If there are fewer than k hotels (in some variants), return all hotels sorted by the same rule.

Solve three OA coding questions

Quick Overview

Question 1: Group strings that are anagrams

Input

Output

Constraints (typical)

Question 2: Maximize an integer by swapping two digits at most once

Input

Output

Constraints (typical)

Question 3: Rank hotels by review sentiment and return top-k

Scoring rules

Task

Input (one reasonable spec)

Output

Constraints (typical)

Notes

Submit Your Answer to Earn 20XP

Solve three OA coding questions

Quick Overview

Question 1: Group strings that are anagrams

Input

Output

Constraints (typical)

Question 2: Maximize an integer by swapping two digits at most once

Input

Output

Constraints (typical)

Question 3: Rank hotels by review sentiment and return top-k

Scoring rules

Task

Input (one reasonable spec)

Output

Constraints (typical)

Notes

Submit Your Answer to Earn 20XP