trie

Longest Common Prefix

Find the longest common prefix in an array of strings, returning an empty string if none exists.

Word Break

Determine if a string can be fully segmented into dictionary words using array scanning and hash-based lookups for effic…

Word Break II

Given a string and dictionary, return all possible sentences by adding spaces where each word is in the dictionary.

Implement Trie (Prefix Tree)

This problem requires designing a Trie (Prefix Tree) to efficiently store and query strings using hash table concepts fo…

Design Add and Search Words Data Structure

Build a WordDictionary supporting dynamic word addition and search with wildcard matching efficiently using Trie and DFS…

Word Search II

Solve the Word Search II problem using backtracking with pruning to find all words on a board of characters.

Palindrome Pairs

Find all pairs of words in a list that form palindromes when concatenated using efficient scanning and hash mapping.

Lexicographical Numbers

Generate all numbers from 1 to n in lexicographical order using a depth-first search pattern optimized with trie logic f…

Maximum XOR of Two Numbers in an Array

Find the maximum XOR of two numbers in an integer array using efficient bit manipulation techniques.

K-th Smallest in Lexicographical Order

Find the k-th lexicographically smallest integer in a range using a Trie-based approach.

Concatenated Words

Find concatenated words by using dynamic programming and depth-first search to identify valid words made of other words …

Replace Words

Replace words in a sentence using the shortest root from a dictionary, applying efficient array scanning and hash lookup…

Implement Magic Dictionary

Design a Magic Dictionary to allow searching with one-character modifications, using Hash Table and String techniques.

Map Sum Pairs

Design and implement a data structure that supports efficient insertion and sum queries based on string prefixes.

Top K Frequent Words

Solve Top K Frequent Words by counting each word, then ordering ties alphabetically so frequency wins before lexicograph…

Longest Word in Dictionary

Find the longest word in a dictionary that can be built one character at a time from other words in the dictionary.

Prefix and Suffix Search

Design a dictionary to search words by both prefix and suffix using a Trie structure and hash lookups.

Number of Matching Subsequences

Given a string s and a list of words, count how many words are subsequences of s using efficient array scanning and hash…

Short Encoding of Words

Find the minimum length of a reference string encoding an array of words using array scanning and hash lookup efficientl…

Camelcase Matching

Camelcase Matching is a medium difficulty problem where you match queries to a given pattern by inserting lowercase lett…

Stream of Characters

Implement a StreamChecker that detects if any suffix of a character stream matches a given list of words using efficient…

Number of Valid Words for Each Puzzle

Solve the "Number of Valid Words for Each Puzzle" problem with array scanning and hash lookup to efficiently count valid…

Remove Sub-Folders from the Filesystem

Remove sub-folders in a filesystem by filtering out folders nested inside other folders.

Search Suggestions System

Design a search suggestion system that provides the top three lexicographically smallest products matching a search word…