Kakao Releases Solutions for 5 Problems from 2022 Summer Internship Coding Test

Kakao released solutions for the 5 problems from the summer internship coding test conducted on May 7, 2022. Unlike last year, this test lasted 5 hours, an increase of 1 hour. Points were awarded only if all test cases were passed for every problem, with no partial credit given. However, for some problems, accuracy and efficiency tests were separated, with additional points awarded for efficient solutions.

The key solution strategies for the main problems are as follows. Problem 2, 'Making the Sum of Two Queues Equal', can be solved using a greedy approach or two-pointer technique by moving the boundary between the queues to balance the sums. Problem 3, 'Studying for Coding Tests', can be solved by defining the states of algorithmic power and coding power in a 2D dynamic programming (DP) array to find the shortest time to the target state, or by modeling it as a graph and using Dijkstra's algorithm. Problem 4, 'Determining Hiking Routes', uses a modified Dijkstra's algorithm to minimize the maximum path weight, reducing time complexity by treating all entrances as starting vertices in a single algorithm execution. Problem 5, 'Matrix and Operations', utilizes a deque or linked list to manage only the row and column indices, performing operations without actual data movement and improving time complexity from O(NMQ) to O(NM+Q).