Memoization LeetCode Problems: All 39, With Python Solutions

Every problem in this library that LeetCode tags Memoization — 39 in total, 38 of them with a complete Python solution, a worked example and the time and space complexity of the approach.

39 problems
3 Easy
11 Medium
25 Hard

How Memoization problems are solved

A tag names the subject, not the method. These pattern hubs cover the techniques that actually solve Memoization problems — each one explains the approach, gives a Python template and states its complexity.

Dynamic Programming — Define a state, write the transition, and stop recomputing the same subproblem.

Memoization problems by difficulty

Problems with a complete Python solution are listed first, then by ascending problem number.

Easy (3)

#	Problem	Difficulty	Topics
70	Climbing Stairs	Easy	Memoization, Math, Dynamic Programming
509	Fibonacci Number	Easy	Recursion, Memoization, Math +1
1137	N-th Tribonacci Number	Easy	Memoization, Math, Dynamic Programming

Medium (11)

#	Problem	Difficulty	Topics
139	Word Break	Medium	Trie, Memoization, Array +3
241	Different Ways to Add Parentheses	Medium	Recursion, Memoization, Math +2
397	Integer Replacement	Medium	Greedy, Bit Manipulation, Memoization +1
464	Can I Win	Medium	Bit Manipulation, Memoization, Math +3
638	Shopping Offers	Medium	Bit Manipulation, Memoization, Array +3
698	Partition to K Equal Sum Subsets	Medium	Bit Manipulation, Memoization, Array +3
894	All Possible Full Binary Trees	Medium	Tree, Recursion, Memoization +2
1387	Sort Integers by The Power Value	Medium	Memoization, Dynamic Programming, Sorting
2311	Longest Binary Subsequence Less Than or Equal to K	Medium	Greedy, Memoization, String +1
2998	Minimum Number of Operations to Make X and Y Equal	Medium	Breadth-First Search, Memoization, Dynamic Programming
294	Flip Game IIPremium	Medium	Memoization, Math, Dynamic Programming +2

Hard (25)

#	Problem	Difficulty	Topics
140	Word Break II	Hard	Trie, Memoization, Array +4
329	Longest Increasing Path in a Matrix	Hard	Depth-First Search, Breadth-First Search, Graph +5
488	Zuma Game	Hard	Stack, Breadth-First Search, Memoization +2
546	Remove Boxes	Hard	Memoization, Array, Dynamic Programming
691	Stickers to Spell Word	Hard	Bit Manipulation, Memoization, Array +5
773	Sliding Puzzle	Hard	Breadth-First Search, Memoization, Array +3
913	Cat and Mouse	Hard	Graph, Topological Sort, Memoization +3
964	Least Operators to Express Number	Hard	Memoization, Math, Dynamic Programming
1444	Number of Ways of Cutting a Pizza	Hard	Memoization, Array, Dynamic Programming +2
1553	Minimum Number of Days to Eat N Oranges	Hard	Memoization, Dynamic Programming
1569	Number of Ways to Reorder Array to Get Same BST	Hard	Tree, Union Find, Binary Search Tree +7
1575	Count All Possible Routes	Hard	Memoization, Array, Dynamic Programming
1611	Minimum One Bit Operations to Make Integers Zero	Hard	Bit Manipulation, Memoization, Dynamic Programming
1659	Maximize Grid Happiness	Hard	Bit Manipulation, Memoization, Dynamic Programming +1
1728	Cat and Mouse II	Hard	Graph, Topological Sort, Memoization +5
1815	Maximum Number of Groups Getting Fresh Donuts	Hard	Bit Manipulation, Memoization, Array +2
1857	Largest Color Value in a Directed Graph	Hard	Graph, Topological Sort, Memoization +3
1900	The Earliest and Latest Rounds Where Players Compete	Hard	Memoization, Dynamic Programming
2019	The Score of Students Solving Math Expression	Hard	Stack, Memoization, Array +4
2312	Selling Pieces of Wood	Hard	Memoization, Array, Dynamic Programming
2318	Number of Distinct Roll Sequences	Hard	Memoization, Dynamic Programming
2328	Number of Increasing Paths in a Grid	Hard	Depth-First Search, Breadth-First Search, Graph +5
2713	Maximum Strictly Increasing Cells in a Matrix	Hard	Memoization, Array, Hash Table +5
2876	Count Visited Nodes in a Directed Graph	Hard	Graph, Memoization, Dynamic Programming
2920	Maximum Points After Collecting Coins From All Nodes	Hard	Bit Manipulation, Tree, Depth-First Search +3

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.

When the Memoization problem arrives live

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