Three fresh LeetCode walkthroughs
Three new LeetCode‑style walkthroughs dropped Mar 29–30 covering string operations, an Event Manager system‑design simulation, and a 'Sum of Sortable Integers' data problem — each is timed‑practice ready for interview prep. Use the videos to simulate 30–45 minute whiteboard rounds and record your explanations for behavioral follow‑ups. (youtube.com 1) (youtube.com 2) (youtube.com 3)
LeetCode problem 2840, "Check if Strings Can be Made Equal With Operations II," is the string walkthrough solved in the first video and the published solutions use parity-based counters that run in O(n) time with O(1) extra space. (walkccc.me) LeetCode problem 3885, "Design Event Manager," requires implementing an EventManager class with methods including initialization, updatePriority(eventId, newPriority), and pollHighest(), and the official statement specifies how ties and removals should behave. (leetcode.com) The Event Manager walkthrough frames the implementation as a systems-simulation of priority-queue tradeoffs and demonstrates techniques such as lazy deletion and pairing a hash map with a heap to meet the API constraints in contest-style examples. (youtube.com) LeetCode problem 3886, "Sum of Sortable Integers," asks for the sum of all divisors k of n for which partitioning nums into k-length blocks and cyclically rotating each block can sort the array; the problem limits include n ≤ 10^5 and nums[i] ≤ 10^5. (leetcode.com) Walkthroughs for 3886 emphasize the (i % k) grouping trick to check each divisor efficiently and present near-linear checks over divisors rather than brute-force rotations, as covered in contest explanations and video walkthroughs. (youtube.com) Problems 3885 and 3886 were published as part of LeetCode Weekly Contest 495 (both appear in the contest problem list for Weekly Contest 495), placing them in the same release window leveraged by multiple solution channels. (clist.by) The string walkthrough appears on the impoldev channel (≈1k subscribers) which has been uploading daily DSA walkthroughs and added this LeetCode 2840 explanation to its playlists alongside other recent hard-problem videos. (youtube.com)
