LinkedIn Coding Interview Questions

Send a message, trust it arrives. An outbox that survives process kills and ordering that holds across reconnects.

Five escalating takes on one bracket string: validate it, point editor squigglies at it, mine the longest valid substring, repair a broken file, and validate with a corruptable wildcard.

Bounded-memory caching: get it correct, then evict the least recently used, then make every operation O(1), then serve recency queries and TTL expiry.

Five levels of lowest-common-ancestor questions: on a binary search tree, on general binary trees, from parent pointers alone, across n-ary org charts, and in bulk batches against a static tree.

One string, four contracts: is it a palindrome, can it become one by deleting at most one character, at most k characters, and what is the exact minimum number of deletions it needs?

A nested list of integers gets three contracts - depth-weighted sum, reverse-weighted sum, then a flatten iterator that yields one integer at a time - with nesting deep enough to strain naive traversals.

Return the kth largest element from a stream of scores, where k=1 is the maximum and duplicates count separately. Levels tighten the budget - bounded memory, average-linear time, and answers that stay current as scores keep arriving.