Advanced Interview Problems

Array Binary Search Dynamic Programming Sorting

Rank

#716HardFrequency: 100%High Priority

Max Stack

Linked List Stack Design Doubly-Linked List Ordered Set

Rank

#42HardFrequency: 100%High Priority

Trapping Rain Water

Array Two Pointers Dynamic Programming Stack Monotonic Stack

Rank

#833HardFrequency: 95%High Priority

Bus Routes

Array Hash Table Breadth-First Search

Rank

#84HardFrequency: 93%High Priority

Largest Rectangle in Histogram

Array Stack Monotonic Stack

Rank

#65HardFrequency: 91%High Priority

Valid Number

String

Rank

#124HardFrequency: 84%High Priority

Binary Tree Maximum Path Sum

Dynamic Programming Tree Depth-First Search Binary Tree

Rank

#273HardFrequency: 82%High Priority

Integer to English Words

Math String Recursion

Rank

#432HardFrequency: 82%High Priority

All O`one Data Structure

Rank

#269HardFrequency: 79%High Priority

Alien Dictionary

Array String Depth-First Search Breadth-First Search Graph+1 more

#10

Rank

#305HardFrequency: 79%High Priority

Number of Islands II

Array Hash Table Union Find

#11

Rank

#329HardFrequency: 79%High Priority

Longest Increasing Path in a Matrix

Array Dynamic Programming Depth-First Search Breadth-First Search Graph+3 more

#12

Rank

#4HardFrequency: 79%High Priority

Median of Two Sorted Arrays

Array Binary Search Divide and Conquer

#13

Rank

#2267HardFrequency: 76%High Priority

Minimum Difference in Sums After Removal of Elements

Asked at TikTok

Array Dynamic Programming Heap (Priority Queue)

#14

Rank

#41HardFrequency: 74%High Priority

First Missing Positive

Array Hash Table

#15

Rank

#1178HardFrequency: 74%High Priority

Valid Palindrome III

String Dynamic Programming

#16

Rank

#2711HardFrequency: 73%High Priority

Minimum Time to Visit a Cell In a Grid

Array Breadth-First Search Graph Heap (Priority Queue)Matrix+1 more

#17

Rank

#3710HardFrequency: 72%High Priority

Design an Array Statistics Tracker

Hash Table Binary Search Design Queue Heap (Priority Queue)+2 more

#18

Rank

#23HardFrequency: 72%High Priority

Merge k Sorted Lists

Linked List Divide and Conquer Heap (Priority Queue)Merge Sort

#19

Rank

#381HardFrequency: 72%High Priority

Insert Delete GetRandom O(1) - Duplicates allowed

Array Hash Table Math Design Randomized

#20

Rank

#10HardFrequency: 70%High Priority

Regular Expression Matching

String Dynamic Programming Recursion

#21

Rank

#1029HardFrequency: 69%High Priority

Vertical Order Traversal of a Binary Tree

Hash Table Tree Depth-First Search Breadth-First Search Sorting+1 more

#22

Rank

#410HardFrequency: 65%High Priority

Split Array Largest Sum

Array Binary Search Dynamic Programming Greedy Prefix Sum

#23

Rank

#127HardFrequency: 64%High Priority

Word Ladder

Hash Table String Breadth-First Search

#24

Rank

#460HardFrequency: 60%High Priority

LFU Cache

#25

Rank

#76HardFrequency: 60%High Priority

Minimum Window Substring

Hash Table String Sliding Window

#26

Rank

#854HardFrequency: 60%High Priority

Making A Large Island

Array Depth-First Search Breadth-First Search Union Find Matrix

#27

Rank

#629HardFrequency: 60%High Priority

K Inverse Pairs Array

Dynamic Programming

#28

Rank

#224HardFrequency: 56%High Priority

Basic Calculator

Math String Stack Recursion

#29

Rank

#25HardFrequency: 55%High Priority

Reverse Nodes in k-Group

Linked List Recursion

#30

Rank

#126HardFrequency: 52%High Priority

Word Ladder II

Hash Table String Backtracking Breadth-First Search

#31

Rank

#3410HardFrequency: 51%High Priority

Find Longest Self-Contained Substring

Hash Table String Binary Search Prefix Sum

#32

Rank

#1034HardFrequency: 50%High Priority

Subarrays with K Different Integers

Asked at DoorDash

Array Hash Table Sliding Window Counting

#33

Rank

#51HardFrequency: 48%High Priority

N-Queens

Array Backtracking

#34

Rank

#295HardFrequency: 48%High Priority

Find Median from Data Stream

Two Pointers Design Sorting Heap (Priority Queue)Data Stream

#35

Rank

#239HardFrequency: 45%High Priority

Sliding Window Maximum

Array Queue Sliding Window Heap (Priority Queue)Monotonic Queue

#36

Rank

#262HardFrequency: 45%High Priority

Trips and Users

Database

#37

Rank

#282HardFrequency: 37%High Priority

Expression Add Operators

Math String Backtracking

#38

Rank

#188HardFrequency: 36%High Priority

Best Time to Buy and Sell Stock IV

Array Dynamic Programming

#39

Rank

#1257HardFrequency: 34%High Priority

Rank Transform of a Matrix

Array (19)Hash Table (13)String (11)Dynamic Programming (10)Breadth-First Search (8)Design (6)Heap (Priority Queue) (6)Binary Search (5)

Array Union Find Graph Topological Sort Sorting+1 more

#40

Rank

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Advanced Interview Problems

Challenging hard problems asked at top-tier tech companies for senior positions.

Total Problems

Easy

Medium

Hard

68%

Avg Frequency

Most Common Topics

Companies Asking These Questions

Amazon (6)Salesforce (5)Oracle (4)Meta (4)Apple (3)Uber (3)

Problems in This Collection

#1352HardFrequency: 100%High Priority

Maximum Profit in Job Scheduling

Array Binary Search Dynamic Programming Sorting

Rank

#716HardFrequency: 100%High Priority

Max Stack

Linked List Stack Design Doubly-Linked List Ordered Set

Rank

#42HardFrequency: 100%High Priority

Trapping Rain Water

Array Two Pointers Dynamic Programming Stack Monotonic Stack

Rank

#833HardFrequency: 95%High Priority

Bus Routes

Array Hash Table Breadth-First Search

Rank

#84HardFrequency: 93%High Priority

Largest Rectangle in Histogram

Array Stack Monotonic Stack

Rank

#65HardFrequency: 91%High Priority

Valid Number

String

Rank

#124HardFrequency: 84%High Priority

Binary Tree Maximum Path Sum

Dynamic Programming Tree Depth-First Search Binary Tree

Rank

#273HardFrequency: 82%High Priority

Integer to English Words

Math String Recursion

Rank

#432HardFrequency: 82%High Priority

All O`one Data Structure

Rank

#269HardFrequency: 79%High Priority

Alien Dictionary

Array String Depth-First Search Breadth-First Search Graph+1 more

#10

Rank

#305HardFrequency: 79%High Priority

Number of Islands II

Array Hash Table Union Find

#11

Rank

#329HardFrequency: 79%High Priority

Longest Increasing Path in a Matrix

Array Dynamic Programming Depth-First Search Breadth-First Search Graph+3 more

#12

Rank

#4HardFrequency: 79%High Priority

Median of Two Sorted Arrays

Array Binary Search Divide and Conquer

#13

Rank

#2267HardFrequency: 76%High Priority

Minimum Difference in Sums After Removal of Elements

Asked at TikTok

Array Dynamic Programming Heap (Priority Queue)

#14

Rank

#41HardFrequency: 74%High Priority

First Missing Positive

Array Hash Table

#15

Rank

#1178HardFrequency: 74%High Priority

Valid Palindrome III

String Dynamic Programming

#16

Rank

#2711HardFrequency: 73%High Priority

Minimum Time to Visit a Cell In a Grid

Array Breadth-First Search Graph Heap (Priority Queue)Matrix+1 more

#17

Rank

#3710HardFrequency: 72%High Priority

Design an Array Statistics Tracker

Hash Table Binary Search Design Queue Heap (Priority Queue)+2 more

#18

Rank

#23HardFrequency: 72%High Priority

Merge k Sorted Lists

Linked List Divide and Conquer Heap (Priority Queue)Merge Sort

#19

Rank

#381HardFrequency: 72%High Priority

Insert Delete GetRandom O(1) - Duplicates allowed

Array Hash Table Math Design Randomized

#20

Rank

#10HardFrequency: 70%High Priority

Regular Expression Matching

String Dynamic Programming Recursion

#21

Rank

#1029HardFrequency: 69%High Priority

Vertical Order Traversal of a Binary Tree

Hash Table Tree Depth-First Search Breadth-First Search Sorting+1 more

#22

Rank

#410HardFrequency: 65%High Priority

Split Array Largest Sum

Array Binary Search Dynamic Programming Greedy Prefix Sum

#23

Rank

#127HardFrequency: 64%High Priority

Word Ladder

Hash Table String Breadth-First Search

#24

Rank

#460HardFrequency: 60%High Priority

LFU Cache

#25

Rank

#76HardFrequency: 60%High Priority

Minimum Window Substring

Hash Table String Sliding Window

#26

Rank

#854HardFrequency: 60%High Priority

Making A Large Island

Array Depth-First Search Breadth-First Search Union Find Matrix

#27

Rank

#629HardFrequency: 60%High Priority

K Inverse Pairs Array

Dynamic Programming

#28

Rank

#224HardFrequency: 56%High Priority

Basic Calculator

Math String Stack Recursion

#29

Rank

#25HardFrequency: 55%High Priority

Reverse Nodes in k-Group

Linked List Recursion

#30

Rank

#126HardFrequency: 52%High Priority

Word Ladder II

Hash Table String Backtracking Breadth-First Search

#31

Rank

#3410HardFrequency: 51%High Priority

Find Longest Self-Contained Substring

Hash Table String Binary Search Prefix Sum

#32

Rank

#1034HardFrequency: 50%High Priority

Subarrays with K Different Integers

Asked at DoorDash

Array Hash Table Sliding Window Counting

#33

Rank

#51HardFrequency: 48%High Priority

N-Queens

Array Backtracking

#34

Rank

#295HardFrequency: 48%High Priority

Find Median from Data Stream

Two Pointers Design Sorting Heap (Priority Queue)Data Stream

#35

Rank

#239HardFrequency: 45%High Priority

Sliding Window Maximum

Array Queue Sliding Window Heap (Priority Queue)Monotonic Queue

#36

Rank

#262HardFrequency: 45%High Priority

Trips and Users

Database

#37

Rank

#282HardFrequency: 37%High Priority

Expression Add Operators

Math String Backtracking

#38

Rank

#188HardFrequency: 36%High Priority

Best Time to Buy and Sell Stock IV

Array Dynamic Programming

#39

Rank

#1257HardFrequency: 34%High Priority

Rank Transform of a Matrix