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Java Collections

List, Set, Map and how to choose between them. 18 problems · Intermediate level.

18 problems

Set

Map

Sort Values by Frequencymedium

maps and caches

sets

Set Operationseasy

deque

Palindrome Check with a Dequeeasy

priority queue

sorted collections

Floor and Ceiling in a Sorted Setmedium

two stacks

Browser History (Back and Forward)medium

hash map internals

Hash Table with Chainingmedium

multiset

Multiset with Countsmedium

heap

Merge k Sorted Listsmedium

map design

Bidirectional Mapmedium

queue deque

Sliding Window Maximum (Deque)hard

maps of sets

Inverted Index Searchhard

queue and map

First Unique Character in a Streamhard