Kakao Releases Solutions for Third Coding Test in New Graduate Recruitment

Kakao has released the content of the five coding test problems and the written exam for the third stage of its new developer recruitment. This test was conducted offline for candidates who passed the online stage, focusing on verifying both coding ability and fundamental computer science knowledge.

Coding Test Difficulty and Correct Answer Rates

The coding test, consisting of a total of five questions, was designed to assess basic implementation skills. The correct answer rates for each problem are as follows:

• N-ary Game: The correct answer rate was 91.85%, the highest among all questions, though C++ users found it relatively difficult.
• Compression (LZW): The correct answer rate was 66.95%, with most candidates solving it successfully.
• File Name Sorting: The correct answer rate was 66.95%. The difficulty varied depending on whether a Stable Sort was implemented, and C++ and Python users found it relatively difficult.
• Just Now Song: The correct answer rate was 47.50%, with Python users performing the best.
• Autocomplete: The correct answer rate was 34.07%, making it the most difficult question, while Java users performed the best. To pass the time limit, candidates needed to utilize the Trie data structure or a method of sorting followed by adjacent comparison.

Written Exam Structure and Evaluation Criteria

The written exam, which remained undisclosed until the day of the test, consisted of 20 questions in total, assessing conceptual explanations based on English Wikipedia and fundamental CS knowledge.

• English Reading Comprehension and Concepts: Questions 1–10 required candidates to read descriptions of computing and internet concepts in English and identify the corresponding terms.
• Network and Software: Question 11 asked about the sequence of the TCP connection termination process (active/passive close), and Question 12 asked about the MVC design pattern.
• Algorithm Analysis: Questions 13–16 were time complexity (Big-O) calculation problems. In particular, Question 16 required an understanding of performance differences based on the selection of sorting targets.
• Data Structures: Questions 17–20 dealt with selecting appropriate data structures and tree traversal calculation problems.