Do you need to know how to sort Java objects in a collection, array, or map? Here's how to use the Comparable and Comparator interfaces and avoid ClassCastExceptions. Programmers frequently need to ...

Arrays Basics, 2D arrays, sliding window, prefix sums, Kadane’s, etc. Foundation for all other DSA problems. Strings Palindromes, anagrams, character frequency, pattern matching Frequently asked in ...