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Citadel Interview Questions (96)

Practice real interview problems from Citadel

All96 Easy6 Medium59 Hard31

Status	Title	Solution	Practice	Difficulty	Companies	Topics
	10. Regular Expression Matching	Solution	Solve	Hard	Accenture+26	Dynamic Programming Recursion+1
	23. Merge k Sorted Lists	Solution	Solve	Hard	Accenture+52	Divide and Conquer Heap (Priority Queue)+2
	37. Sudoku Solver	Solution	Solve	Hard	Adobe+17	Array Backtracking+2
	42. Trapping Rain Water	Solution	Solve	Hard	Accenture+77	Array Dynamic Programming+3
	123. Best Time to Buy and Sell Stock III	Solution	Solve	Hard	Adobe+14	Array Dynamic Programming
	124. Binary Tree Maximum Path Sum	Solution	Solve	Hard	Amazon+24	Binary Tree Depth-First Search+2
	126. Word Ladder II	Solution	Solve	Hard	Amazon+13	Backtracking Breadth-First Search+2
	127. Word Ladder	Solution	Solve	Hard	Adobe+36	Breadth-First Search Hash Table+1
	149. Max Points on a Line	Solution	Solve	Hard	Amazon+15	Array Geometry+2
	188. Best Time to Buy and Sell Stock IV	Solution	Solve	Hard	Amazon+10	Array Dynamic Programming
	239. Sliding Window Maximum	Solution	Solve	Hard	Adobe+47	Array Heap (Priority Queue)+3
	295. Find Median from Data Stream	Solution	Solve	Hard	Amazon+37	Data Stream Design+3
	297. Serialize and Deserialize Binary Tree	Solution	Solve	Hard	Adobe+26	Binary Tree Breadth-First Search+4
	332. Reconstruct Itinerary	Solution	Solve	Hard	Amazon+21	Depth-First Search Eulerian Circuit+1
	460. LFU Cache	Solution	Solve	Hard	Amazon+30	Design Doubly-Linked List+2
	465. Optimal Account Balancing	Solution	Solve	Hard	Affirm+10	Array Backtracking+3
	631. Design Excel Sum Formula	Solution	Solve	Hard	Airbnb+8	Array Design+3
	642. Design Search Autocomplete System	Solution	Solve	Hard	Amazon+13	Data Stream Depth-First Search+5
	759. Employee Free Time	Solution	Solve	Hard	Airbnb+12	Array Heap (Priority Queue)+1
	765. Couples Holding Hands	Solution	Solve	Hard	Bloomberg+3	Breadth-First Search Depth-First Search+3
	782. Transform to Chessboard	Solution	Solve	Hard	Citadel+1	Array Bit Manipulation+2
	1192. Critical Connections in a Network	Solution	Solve	Hard	Akuna Capital+8	Biconnected Component Depth-First Search+1
	1203. Sort Items by Groups Respecting Dependencies	Solution	Solve	Hard	Amazon+4	Breadth-First Search Depth-First Search+2
	1235. Maximum Profit in Job Scheduling	Solution	Solve	Hard	Airbnb+23	Array Binary Search+2
	1515. Best Position for a Service Centre	Solution	Solve	Hard	Citadel	Array Geometry+2
	1606. Find Servers That Handled Most Number of Requests	Solution	Solve	Hard	Amazon+5	Array Greedy+2
	1632. Rank Transform of a Matrix	Solution	Solve	Hard	Citadel+2	Array Graph+4
	2050. Parallel Courses III	Solution	Solve	Hard	Acko+7	Array Dynamic Programming+2
	2361. Minimum Costs Using the Train Line	Solution	Solve	Hard	Citadel	Array Dynamic Programming
	2484. Count Palindromic Subsequences	Solution	Solve	Hard	Amazon+10	Dynamic Programming String
	2702. Minimum Operations to Make Numbers Non-positive	Solution	Solve	Hard	Citadel+1	Array Binary Search

Regular Expression Matching

Hard✓ Solution

Accenture+26

Dynamic Programming Recursion String

Merge k Sorted Lists

Hard✓ Solution📹 Video

Accenture+52

Divide and Conquer Heap (Priority Queue)Linked List+1

Sudoku Solver

Hard✓ Solution

Adobe+17

Array Backtracking Hash Table+1

Trapping Rain Water

Hard✓ Solution

Accenture+77

Array Dynamic Programming Monotonic Stack+2

Best Time to Buy and Sell Stock III

Hard✓ Solution

Adobe+14

Array Dynamic Programming

Binary Tree Maximum Path Sum

Hard✓ Solution

Amazon+24

Binary Tree Depth-First Search Dynamic Programming+1

Word Ladder II

Hard✓ Solution📹 Video

Amazon+13

Backtracking Breadth-First Search Hash Table+1

Word Ladder

Hard✓ Solution📹 Video

Adobe+36

Breadth-First Search Hash Table String

Max Points on a Line

Hard✓ Solution

Amazon+15

Array Geometry Hash Table+1

Best Time to Buy and Sell Stock IV

Hard✓ Solution

Amazon+10

Array Dynamic Programming

Sliding Window Maximum

Hard✓ Solution

Adobe+47

Array Heap (Priority Queue)Monotonic Queue+2

Find Median from Data Stream

Hard✓ Solution

Amazon+37

Data Stream Design Heap (Priority Queue)+2

Serialize and Deserialize Binary Tree

Hard✓ Solution

Adobe+26

Binary Tree Breadth-First Search Depth-First Search+3

Reconstruct Itinerary

Hard

Amazon+21

Depth-First Search Eulerian Circuit Graph

LFU Cache

Hard✓ Solution

Amazon+30

Design Doubly-Linked List Hash Table+1

Optimal Account Balancing

Hard✓ Solution

Affirm+10

Array Backtracking Bit Manipulation+2

Design Excel Sum Formula

Hard✓ Solution

Airbnb+8

Array Design Graph+2

Design Search Autocomplete System

Hard✓ Solution

Amazon+13

Data Stream Depth-First Search Design+4

Employee Free Time

Hard📹 Video

Airbnb+12

Array Heap (Priority Queue)Sorting

Couples Holding Hands

Hard✓ Solution

Bloomberg+3

Breadth-First Search Depth-First Search Graph+2

Transform to Chessboard

Hard✓ Solution

Citadel+1

Array Bit Manipulation Math+1

Critical Connections in a Network

Hard✓ Solution

Akuna Capital+8

Biconnected Component Depth-First Search Graph

Sort Items by Groups Respecting Dependencies

Hard✓ Solution📹 Video

Amazon+4

Breadth-First Search Depth-First Search Graph+1

Maximum Profit in Job Scheduling

Hard✓ Solution📹 Video

Airbnb+23

Array Binary Search Dynamic Programming+1

Best Position for a Service Centre

Hard

Citadel

Array Geometry Math+1

Find Servers That Handled Most Number of Requests

Hard✓ Solution

Amazon+5

Array Greedy Heap (Priority Queue)+1

Rank Transform of a Matrix

Hard✓ Solution

Citadel+2

Array Graph Matrix+3

Parallel Courses III

Hard✓ Solution📹 Video

Acko+7

Array Dynamic Programming Graph+1

Minimum Costs Using the Train Line

Hard✓ Solution📹 Video

Citadel

Array Dynamic Programming

Count Palindromic Subsequences

Hard

Amazon+10

Dynamic Programming String

Minimum Operations to Make Numbers Non-positive

Hard

Citadel+1

Array Binary Search