This is a premium problem. We're working on making it available for free soon.
Use these hints if you're stuck. Try solving on your own first.
Add all the words to a trie.
Check the longest path where all the nodes are words.
Solutions for this premium problem will be available for free soon.
Browse Free ProblemsWatch expert explanations and walkthroughs
Practice problems asked by these companies to ace your technical interviews.
Explore More ProblemsJot down your thoughts, approach, and key learnings
DFS helps explore all valid word paths in the Trie while ensuring that each prefix node represents a completed word. This allows us to build candidate words incrementally and track the longest valid one during traversal.
Yes, variations of this problem appear in technical interviews at major tech companies. It tests understanding of Trie data structures, prefix handling, and DFS traversal, which are common topics in coding interviews.
The optimal approach is to build a Trie from all the words and perform a DFS traversal that only follows nodes representing complete words. This guarantees that every prefix of the current word exists in the dictionary while exploring candidates efficiently.
A Trie is the best data structure because it naturally represents prefix relationships between words. It allows efficient insertion and enables prefix validation during traversal without repeatedly checking substrings.