Valid Anagram
Recognize the pattern
Brute force idea
A straightforward first read of Valid Anagram is this: Sort both strings and compare. That instinct is useful because it follows the prompt literally, but it usually keeps revisiting work the problem is begging you to organize.
Better approach
The real unlock in Valid Anagram comes when you notice this: Count character frequencies with a hash map; compare counts (26 letters). Instead of recomputing the world every time, you preserve just enough context to let the next decision become obvious.
Key invariant
The compass for Valid Anagram is this: Two strings are anagrams if and only if they have identical character frequency counts. As long as that statement keeps holding, you can trust the steps built on top of it.
Watch out for
A common way to get lost in Valid Anagram is this: Forgetting to handle different lengths — check lengths first as an early exit. Most mistakes here are not about syntax; they come from losing track of what your state, pointer, or structure is supposed to mean.