Checking for nearby repeated events in a log or sensor stream is a common task in monitoring, fraud detection, and real‑time analytics....

Finding the longest run of consecutive days, IDs, or timestamps in a dataset comes up in analytics, event processing, and scheduling systems. This “Longest Consecutive Sequence” problem is a great way to exercise hashing, set membership, and thinking about how to avoid redundant work.

Finding how many contiguous stretches of transactions sum to a target turns up in budgeting tools, analytics dashboards, and real‑time...

Clustering words that are anagrams of each other is a classic interview problem and mirrors real‑world tasks like building search indexes...

Circular queues (ring buffers) come up in real‑world systems like streaming data buffers, IO scheduling, and task schedulers. They let...

Flattening a multilevel doubly linked list pops up in real‑world scenarios like expanding nested comment threads or unfolding embedded...

I’m staring at my whiteboard, fresh off writing the brute‑force substring search: two nested loops, compare needle at every haystack...