01 — problem
Permutation in String — LeetCode #?. Full problem statement, examples, and constraints live at https://leetcode.com/problems/permutation-in-string. PatternLens tracks this problem for pattern coverage and progress tracking.
02 — notes
Full examples and constraints live on the original LeetCode prompt. Use the link in the sidebar when you want the canonical statement.
03 — hints
Start by identifying the core sliding window - fixed size idea that reduces the search space.
If you get stuck, check whether a standard sliding window - fixed size technique applies here.