midStrings
Count total number of substrings in a string.
Updated Apr 28, 2026
Short answer
A string of length n has n(n+1)/2 substrings.
Deep explanation
Intermediate string problems test your ability to use frequency maps and sliding windows. A string of length n has n(n+1)/2 substrings.
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?