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Algorithms you can see — 100% free.

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0-day streakApprentice

0 XP · 0/638 understood

Daily goal 0/1

Prep plan Browse all

Learn the Basics44

Sorting Techniques11

Arrays & Hashing51

Sliding Window20

Binary Search51

Bit Manipulation24

Heap / Priority Queue21

Binary Search Trees21

Depth-First Search25

Breadth-First Search10

OverviewPrefix tree · shared prefixes stored once
Implement Trieinsert · search · startsWith
Practice problems
Trie Implementation and Operationsinsert, search, startsWith
Trie Implementation and Advanced OperationsCounts at every node
Longest Word with All PrefixesEvery prefix must itself be a word
Number of distinct substrings in a stringInsert every suffix; count the nodes
Bit PreRequisites for TRIE ProblemsA binary trie over the bits of a number
Maximum XOR of two numbers in an arrayGreedily take the opposite bit at every level
Maximum Xor with an element from an arraySort both sides and insert as the limit rises
Prefix MatchingWalk the prefix, read the count

Dynamic Programming65

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Trie

Prefix tree — shared prefixes stored once, fast lookups.

0/ 10 understood · 0%

Walkthroughs: 6
Problems: 10

10 shown

OverviewPrefix tree · shared prefixes stored onceanimatedMedium
Implement Trieinsert · search · startsWithanimatedMedium
Practice problems
Trie Implementation and Operationsinsert, search, startsWithanimatedHard
Trie Implementation and Advanced OperationsCounts at every nodeanimatedHard
Longest Word with All PrefixesEvery prefix must itself be a wordanimatedMedium
Number of distinct substrings in a stringInsert every suffix; count the nodesMedium
Bit PreRequisites for TRIE ProblemsA binary trie over the bits of a numberEasy
Maximum XOR of two numbers in an arrayGreedily take the opposite bit at every levelHard
Maximum Xor with an element from an arraySort both sides and insert as the limit risesHard
Prefix MatchingWalk the prefix, read the countanimatedMedium