LinkedIn's DSA rounds draw heavily from strings/sliding-window, stack-based design problems, and graph/BFS patterns — and interviewers consistently push candidates past a first working solution toward a more optimized one. The three problems below are real, recently reported (2025) LinkedIn questions with full solutions.
Design a stack that supports the usual push, pop and top operations, plus peekMax (return the maximum element without removing it) and popMax (remove and return the maximum element).
Input: push(5), push(1), push(5), popMax(), top(), popMax()
Output: 5, 1, 1
After removing one of the two 5s, the next popMax removes the remaining 1 (the new maximum among what's left).
Given strings s and t, find the smallest substring of s that contains every character of t (with multiplicity). As a follow-up, treat s as circular — the window is allowed to wrap around from the end of s back to the beginning.
Input: s = "ADOBECODEBANC", t = "ABC"
Output: "BANC"
Given a beginWord, an endWord and a word list, find the length of the shortest transformation sequence from beginWord to endWord, changing exactly one letter at a time, where every intermediate word must exist in the word list.
Input: beginWord = "hit", endWord = "cog", wordList = ["hot","dot","dog","lot","log","cog"]
Output: 5
"hit" -> "hot" -> "dot" -> "dog" -> "cog"
More DSA topics LinkedIn has asked recently
These topic areas reflect patterns commonly reported in recent LinkedIn loops. Full problem statements, solutions and explanations for these are part of the Placement-Ready PYQ Kit.
5 more verified DSA questions with full solutions in the full Placement-Ready PYQ Kit
Includes every round they were asked in, from Phone Screen through the onsite loop.