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Arrays & Hashing
Arrays are the simplest and most common data structure. Hashing (Hash Maps and Hash Sets) provides O(1) average time complexity for lookups, making it an essential tool for optimizing array problems.
Problems (13)
- Contains DuplicateDifficulty: Easy
- Encode and Decode StringsDifficulty: Medium
- Find the Index of the First Occurrence in a StringDifficulty: Easy
- Group AnagramsDifficulty: Medium
- Longest Consecutive SequenceDifficulty: Medium
- Majority ElementDifficulty: Easy
- Product of Array Except SelfDifficulty: Medium
- Rotate ArrayDifficulty: Medium
- Subarray Sum Equals KDifficulty: Medium
- Top K Frequent ElementsDifficulty: Medium
- Two SumDifficulty: Easy
- Valid AnagramDifficulty: Easy
- Valid SudokuDifficulty: Medium