1582 articles
The four canonical string DP problems — edit distance, longest common subsequence, interleaving strings, and regular expression matching — share a common 2D state structure. Master the family and you cover 80 percent of FAANG string DP questions.
Group anagrams, find anagram occurrences, and detect anagrams under constraints. Master the three classical encodings — sorted key, 26-bucket frequency vector, and prime-product hash — with rolling-window extensions used at Meta and Google.
Longest Palindromic Substring, Palindrome Partitioning, and Palindromic Substrings form a tight family of FAANG questions. Master expand-around-center, 2D DP, and the link to Manacher and you can adapt to any variant on the spot.
Word Search II (LC 212) is the canonical FAANG hard combining trie data structures with grid backtracking. Build a trie from the dictionary, DFS each cell, and prune aggressively to convert an exponential brute force into a fast practical algorithm.
Encode and Decode Strings (LC 271) is a deceptively simple FAANG question that mirrors how real protocols frame variable-length payloads. Master length-prefix encoding and you have the foundation for HTTP chunked transfer, Protobuf, and most binary wire formats.