Autocomplete / Suggestions
Problem Statement
Given a prefix, return all words from the trie that start with this prefix (autocomplete feature).
Example: Prefix = "app", Words = ["apple","app","application"] → ["apple","app","application"]
Approach: Trie DFS
Explanation: Traverse trie to prefix node, then DFS from that node to collect all words.
Time Complexity: O(P + K*L), P = prefix length, K = #words with prefix, L = avg word length
Space Complexity: O(N*L) for trie