String Compression (e.g., aabcccccaaa -> a2b1c5a3).

Updated Apr 28, 2026

Short answer

Iterate and count consecutive identical characters, appending count to result.

Deep explanation

Intermediate string problems test your ability to use frequency maps and sliding windows. Iterate and count consecutive identical characters, appending count to result.

Real-world example

Search filters that ignore character order.

Common mistakes

  • Inefficiently sorting strings for an anagram check when a frequency map is O(n).

Follow-up questions

  • What is the time complexity of sorting?

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