Design Patterns — DSA Pattern

The Design Patterns pattern applies when you need tries, LRU/LFU cache, and data structure design. Its time complexity is O(1) or O(log n) per operation, depending on which data structure is being designed (e.g. hash + doubly-linked-list caches vs. heap-based designs) and space complexity O(n). It is used in 35 problems on Thita, including All O`one Data Structure, Design Add and Search Words Data Structure and Design a Stack With Increment Operation. Common variations are Tries and Design (General/Specific).

Master data structure design including LRU/LFU cache, Trie, Min Stack, and system design problems. Implement efficient data structures for interviews.

Design Patterns is pattern 15 of 16 in the Thita.ai DSA course. It covers tries, LRU/LFU cache, and data structure design, split into 2 subpatterns and about 1.5 hours of study. It is a depth pattern: reach for it once the interview-critical patterns are solid.

Subpatterns of Design Patterns

Each subpattern below has its own theory page and problem set. They are listed in the order the course teaches them.

  • Tries — Implement Trie data structure for prefix-based operations and autocomplete systems. (depth topic)
  • Design (General/Specific) — Design and implement data structures: LRU cache, LFU cache, HashMap, and specialized structures. (depth topic)

How to practise Design Patterns on Thita.ai

Read the theory for a subpattern, then solve its problems in the browser editor. Your solution runs against the problem's test cases, and the AI coach gives a hint on the technique you are missing rather than the finished answer. Progress is tracked per subpattern, so the tracker shows which of the 2 Design Patterns subpatterns you have covered. Topics covered here include design patterns, data structure design, LRU cache, LFU cache, Trie implementation, Min Stack, system design, leetcode design.

Related DSA patterns

Preparing this lesson and its course outline.