1582 articles
LeetCode 3043 — find the longest common prefix length between any number in arr1 and any number in arr2 (compared as digit strings). A digit trie of arr1 makes each arr2 lookup O(D) where D is the number of digits.
Map of every important trie variant you need for FAANG interviews — binary trie for XOR, reverse trie for suffix matching, counted trie for prefix scoring, offline trie for bounded queries, and the design patterns that compose them.
Count the number of distinct substrings of a string. The elegant trick: every substring is a prefix of some suffix, so a suffix trie has exactly one node per distinct non-empty substring. Count nodes during insertion in O(N^2).
Complete Tries cheatsheet for FAANG interviews: core operations, 5 patterns, binary trie for XOR, decision guide, complexity table, and problem index covering all 20 trie problems.
Master the two pointer and sliding window patterns that drive 15-20 percent of FAANG array and string interviews at Meta, Google, Amazon, Apple, and Netflix. This guide indexes 60 problems and the techniques behind every variant.