Worked Solutions

397 problems · 468 approaches. Each is stated brute-force first, then optimal, with the idea, time/space complexity and code. Pick a topic — split into separate pages so each loads fast.

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Array52 problems · 69 approaches String44 problems · 49 approaches LinkedList36 problems · 40 approaches Searching & Sorting35 problems · 40 approaches Stacks & Queues36 problems · 36 approaches Binary Trees19 problems · 30 approaches Binary Search Trees16 problems · 17 approaches Heap18 problems · 21 approaches Graph38 problems · 43 approaches Dynamic Programming30 problems · 43 approaches BackTracking18 problems · 20 approaches Bit Manipulation13 problems · 14 approaches Matrix14 problems · 16 approaches Trie8 problems · 8 approaches Greedy17 problems · 18 approaches Design3 problems · 4 approaches