Trie LeetCode Problems: All 49, With Python Solutions
Every problem in this library that LeetCode tags Trie — 49 in total, 36 of them with a complete Python solution, a worked example and the time and space complexity of the approach.
- 49 problems
- 3 Easy
- 24 Medium
- 22 Hard
How Trie problems are solved
A tag names the subject, not the method. These pattern hubs cover the techniques that actually solve Trie problems — each one explains the approach, gives a Python template and states its complexity.
- Trie — Store a set of words by their shared prefixes so lookups cost the length of the word.
Trie problems by difficulty
Problems with a complete Python solution are listed first, then by ascending problem number.
Easy (3)
| # | Problem | Difficulty | Topics |
|---|---|---|---|
| 14 | Longest Common Prefix | Easy | Trie, Array, String |
| 2932 | Maximum Strong Pair XOR I | Easy | Bit Manipulation, Trie, Array +2 |
| 1065 | Index Pairs of a StringPremium | Easy | Trie, Array, String +1 |
Medium (24)
| # | Problem | Difficulty | Topics |
|---|---|---|---|
| 139 | Word Break | Medium | Trie, Memoization, Array +3 |
| 208 | Implement Trie (Prefix Tree) | Medium | Design, Trie, Hash Table +1 |
| 211 | Design Add and Search Words Data Structure | Medium | Depth-First Search, Design, Trie +1 |
| 386 | Lexicographical Numbers | Medium | Depth-First Search, Trie |
| 421 | Maximum XOR of Two Numbers in an Array | Medium | Bit Manipulation, Trie, Array +1 |
| 648 | Replace Words | Medium | Trie, Array, Hash Table +1 |
| 676 | Implement Magic Dictionary | Medium | Depth-First Search, Design, Trie +2 |
| 677 | Map Sum Pairs | Medium | Design, Trie, Hash Table +1 |
| 692 | Top K Frequent Words | Medium | Trie, Array, Hash Table +5 |
| 720 | Longest Word in Dictionary | Medium | Trie, Array, Hash Table +2 |
| 792 | Number of Matching Subsequences | Medium | Trie, Array, Hash Table +4 |
| 820 | Short Encoding of Words | Medium | Trie, Array, Hash Table +1 |
| 1023 | Camelcase Matching | Medium | Trie, Array, Two Pointers +2 |
| 1233 | Remove Sub-Folders from the Filesystem | Medium | Depth-First Search, Trie, Array +1 |
| 1268 | Search Suggestions System | Medium | Trie, Array, String +3 |
| 2261 | K Divisible Elements Subarrays | Medium | Trie, Array, Hash Table +3 |
| 2452 | Words Within Two Edits of Dictionary | Medium | Trie, Array, String |
| 2707 | Extra Characters in a String | Medium | Trie, Array, Hash Table +2 |
| 616 | Add Bold Tag in StringPremium | Medium | Trie, Array, Hash Table +2 |
| 758 | Bold Words in StringPremium | Medium | Trie, Array, Hash Table +2 |
| 1166 | Design File SystemPremium | Medium | Design, Trie, Hash Table +1 |
| 1698 | Number of Distinct Substrings in a StringPremium | Medium | Trie, String, Suffix Array +2 |
| 1804 | Implement Trie II (Prefix Tree)Premium | Medium | Design, Trie, Hash Table +1 |
| 1858 | Longest Word With All PrefixesPremium | Medium | Depth-First Search, Trie, Array +1 |
Hard (22)
| # | Problem | Difficulty | Topics |
|---|---|---|---|
| 140 | Word Break II | Hard | Trie, Memoization, Array +4 |
| 212 | Word Search II | Hard | Trie, Array, String +2 |
| 336 | Palindrome Pairs | Hard | Trie, Array, Hash Table +1 |
| 440 | K-th Smallest in Lexicographical Order | Hard | Trie |
| 472 | Concatenated Words | Hard | Depth-First Search, Trie, Array +3 |
| 745 | Prefix and Suffix Search | Hard | Design, Trie, Array +2 |
| 1032 | Stream of Characters | Hard | Design, Trie, Array +2 |
| 1178 | Number of Valid Words for Each Puzzle | Hard | Bit Manipulation, Trie, Array +2 |
| 1316 | Distinct Echo Substrings | Hard | Trie, String, Hash Function +1 |
| 1707 | Maximum XOR With an Element From Array | Hard | Bit Manipulation, Trie, Array |
| 1803 | Count Pairs With XOR in a Range | Hard | Bit Manipulation, Trie, Array |
| 1948 | Delete Duplicate Folders in System | Hard | Trie, Array, Hash Table +2 |
| 2227 | Encrypt and Decrypt Strings | Hard | Design, Trie, Array +2 |
| 2416 | Sum of Prefix Scores of Strings | Hard | Trie, Array, String +1 |
| 2935 | Maximum Strong Pair XOR II | Hard | Bit Manipulation, Trie, Array +2 |
| 2977 | Minimum Cost to Convert String II | Hard | Graph, Trie, Array +3 |
| 425 | Word SquaresPremium | Hard | Trie, Array, String +1 |
| 527 | Word AbbreviationPremium | Hard | Greedy, Trie, Array +2 |
| 588 | Design In-Memory File SystemPremium | Hard | Design, Trie, Hash Table +2 |
| 642 | Design Search Autocomplete SystemPremium | Hard | Depth-First Search, Design, Trie +4 |
| 1938 | Maximum Genetic Difference Query | Hard | Bit Manipulation, Depth-First Search, Trie +2 |
| 2479 | Maximum XOR of Two Non-Overlapping SubtreesPremium | Hard | Tree, Depth-First Search, Graph +1 |
Keep exploring
All LeetCode topicsEvery tag with a page of its own, with the number of problems behind each.LeetCode patternsThe techniques themselves, with a Python template and complexity for each.Curated study listsBlind 75, NeetCode 150 and three more, grouped by pattern.Easy problemsStart here when the data structure is new rather than the problem.
Other topics
- Array1,569
- String672
- Hash Table588
- Math485
- Dynamic Programming481
- Sorting392
- Greedy346
- Depth-First Search289
- Binary Search253
- Database249
- Tree225
- Breadth-First Search223
- Matrix216
- Two Pointers201
- Bit Manipulation194
- Binary Tree174
- Heap (Priority Queue)163
- Prefix Sum157
- Stack157
- Simulation144
- Graph138
- Counting126
- Design122
- Sliding Window116
When the Trie problem arrives live
Stealth Interview is a desktop app for macOS and Windows. It reads the coding problem off your screen, returns a working solution with a step-by-step explanation and its time and space complexity, and transcribes what the interviewer is saying — while staying invisible to screen sharing.