Hulu, a leading streaming service, is renowned for its innovative technology and engaging content. Securing a software engineering role at Hulu often involves navigating a rigorous interview process, with LeetCode-style coding challenges forming a core component. These questions are designed to assess your algorithmic thinking, data structure knowledge, and problem-solving abilities under pressure. Preparing specifically for common patterns and frequently asked questions at Hulu can significantly boost your confidence and performance. This guide compiles a comprehensive list of 30 common Hulu LeetCode interview questions, offering insights into why they are asked, how to approach them, and example answers to help you master your coding interview.
What Are Hulu LeetCode Interview Questions?
Hulu LeetCode interview questions are algorithmic and data structure problems similar to those found on the LeetCode platform, tailored to assess a candidate's technical proficiency for software engineering roles. These questions cover a broad spectrum of topics, including array manipulation, string processing, linked lists, trees, graphs, dynamic programming, and more. Hulu interviewers use these problems to evaluate your ability to write efficient, bug-free code, analyze time and space complexity, and articulate your thought process clearly. While no official list exists, trends indicate a focus on foundational patterns and frequently encountered problems across top tech companies, often involving practical application of core computer science concepts.
Why Do Interviewers Ask Hulu LeetCode Interview Questions?
Interviewers at Hulu, like many other tech companies, ask LeetCode-style questions to gain a deep understanding of a candidate's fundamental computer science skills. They are looking beyond just a correct answer; they want to see your problem-solving methodology, your ability to break down complex problems into manageable steps, and your command over various data structures and algorithms. These questions reveal how you handle edge cases, optimize solutions for performance, and communicate your thought process effectively. It demonstrates your potential to contribute to their engineering challenges, which often involve optimizing large-scale systems, managing vast datasets, and developing robust, scalable applications. It's a test of your analytical rigor and practical coding prowess.
Two Sum
Longest Substring Without Repeating Characters
Merge Intervals
Binary Tree Level Order Traversal
Word Break
Rotate Array
Add Two Numbers
Valid Parentheses
Climbing Stairs
Number of Islands
Copy List with Random Pointer
Lowest Common Ancestor of a Binary Tree
Maximum Subarray
Product of Array Except Self
Subsets
Find Median from Data Stream
Course Schedule
LRU Cache Implementation
Sliding Window Maximum
Longest Palindromic Substring
Find Kth Largest Element
Serialize and Deserialize Binary Tree
Top K Frequent Elements
Search in Rotated Sorted Array
Trapping Rain Water
Word Search
Palindrome Partitioning
Design Twitter
Alien Dictionary
Meeting Rooms II
Preview List
1. How do you find two numbers in an array that sum to a target?
Why you might get asked this:
Tests basic array manipulation, hash map usage for efficiency, and understanding of time complexity. It's a fundamental problem.
How to answer:
Use a hash map to store numbers seen and their indices. Iterate through the array; for each number, check if target - current_number exists in the map.
Example answer:
Iterate through the array. For each num, calculate complement = target - num. Check if complement is in the hash map. If yes, return [map[complement], index]. Otherwise, add num and its index to the map.
2. How to find the longest substring without repeating characters?
Why you might get asked this:
Evaluates understanding of string manipulation and the sliding window technique, often combined with hash sets or maps.
How to answer:
Use a sliding window. Expand the window rightwards, adding characters to a set. If a duplicate is found, shrink the window from the left until no duplicates.
Example answer:
Maintain a charset and two pointers, left and right. Move right. If s[right] is in charset, remove s[left] and increment left until it's not. Add s[right] to char_set, update max length.
3. How to merge overlapping intervals?
Why you might get asked this:
Checks sorting algorithms, interval handling, and logic for merging overlapping ranges, common in scheduling problems.
How to answer:
Sort intervals by their start times. Iterate, merging an interval with the next if they overlap. Otherwise, add the current interval to the result.
Example answer:
Sort intervals by start_time. Initialize merged list with first interval. Iterate from second interval: if current overlaps with last in merged, update end. Else, append current to merged.
4. How to traverse a binary tree level by level?
Why you might get asked this:
Tests knowledge of tree data structures and Breadth-First Search (BFS) using a queue. Essential for tree processing.
How to answer:
Use a queue. Add the root. In a loop, dequeue a node, process it, then enqueue its left and right children. Repeat level by level.
Example answer:
Initialize a queue with the root. While queue is not empty, get current level size. Process each node in current level: dequeue, add value to levelnodes, enqueue children. Add levelnodes to result.
5. Can a string be segmented into dictionary words?
Why you might get asked this:
Assesses dynamic programming (DP) or backtracking with memoization. A classic problem for string decomposition.
How to answer:
Use DP. dp[i] is true if s[0...i-1] can be segmented. Iterate j from 0 to i-1. If dp[j] is true and s[j...i-1] is in dictionary, then dp[i] is true.
Example answer:
Create dp array of size len(s) + 1, dp[0] = true. Iterate i from 1 to len(s). For each i, iterate j from 0 to i-1. If dp[j] is true and s[j:i] is in wordDict, set dp[i] = true and break. Return dp[len(s)].
6. How to rotate an array by k positions?
Why you might get asked this:
Evaluates array manipulation skills and ability to optimize space/time complexity (e.g., using reverse technique or in-place rotation).
How to answer:
Handle k % n. Reverse the entire array. Then reverse the first k elements, and finally reverse the remaining n-k elements.
Example answer:
Calculate effective k = k % len(nums). Reverse nums[0:len(nums)-k], then nums[len(nums)-k:len(nums)]. Finally, reverse the entire nums array.
7. How to add two numbers represented by linked lists?
Why you might get asked this:
Tests linked list manipulation, handling carry-overs, and constructing new lists. Common for data representation.
How to answer:
Iterate through both lists simultaneously, adding corresponding digits and a carry. Create a new linked list for the sum, propagating carry.
Example answer:
Initialize dummy head and current node. Loop while l1 or l2 or carry exist. Get digits, calculate sum and new carry. Create new node sum % 10, attach it. Move l1, l2, current pointers.
8. How to check if a string of parentheses is valid?
Why you might get asked this:
Tests stack data structure usage for matching opening and closing brackets, a common parsing problem.
How to answer:
Use a stack. Push opening brackets. When a closing bracket appears, pop from stack and check for a match. Stack must be empty at the end.
Example answer:
Initialize empty stack and map of brackets. Iterate through string s. If char is opening bracket, push. If closing, pop from stack. If stack empty or no match, return False. Return True if stack is empty.
9. How many distinct ways to climb stairs?
Why you might get asked this:
A classic dynamic programming or recursion with memoization problem, illustrating the Fibonacci sequence pattern.
How to answer:
This is a Fibonacci sequence. dp[i] is ways to climb i stairs. dp[i] = dp[i-1] + dp[i-2]. Base cases: dp[1]=1, dp[2]=2.
Example answer:
If n <= 2, return n. Create dp array. dp[1]=1, dp[2]=2. Iterate from i=3 to n, dp[i] = dp[i-1] + dp[i-2]. Return dp[n].
10. How to count the number of islands in a grid?
Why you might get asked this:
Evaluates graph traversal (DFS/BFS) on a grid. Tests connectivity and marking visited nodes to avoid re-counting.
How to answer:
Iterate through grid. If '1' found, increment island count and start DFS/BFS from it, marking all connected '1's as visited ('0').
Example answer:
Initialize count = 0. Iterate row, col. If grid[row][col] == '1', count++. Call DFS/BFS to mark all connected '1's to '0'.
11. How to copy a linked list with random pointers?
Why you might get asked this:
A challenging linked list problem testing deep copy, handling cycles, and map usage for mapping original nodes to copies.
How to answer:
First pass: create copy nodes and interweave them (original -> copy -> original -> copy). Second pass: assign random pointers for copies. Third pass: separate original and copy lists.
Example answer:
First, iterate to create node.next copies: orig -> copy -> orig -> copy. Second, iterate to set copy.random based on orig.random.next. Third, separate the lists into original and copy.
12. How to find the lowest common ancestor in a binary tree?
Why you might get asked this:
Tests tree traversal (DFS) and understanding of tree properties. A common interview question for tree knowledge.
How to answer:
Use recursion (DFS). If current node is p or q, return current node. Recursively call on left and right children. If both return non-null, current node is LCA.
Example answer:
Base case: if root is null or p or q, return root. Recursively call lca(root.left, p, q) and lca(root.right, p, q). If both results are non-null, root is LCA. If only one is non-null, return that.
13. How to find the maximum sum of a contiguous subarray?
Why you might get asked this:
Kadane's algorithm is a classic dynamic programming problem, testing optimization for maximum sum.
How to answer:
Use Kadane's algorithm. Maintain currentmax and globalmax. currentmax is max(num, num + currentmax). globalmax is max(globalmax, current_max).
Example answer:
Initialize maxsofar = nums[0] and currentmax = nums[0]. Iterate from second element: currentmax = max(nums[i], currentmax + nums[i]). maxsofar = max(maxsofar, currentmax). Return maxsofar.
14. How to find product of array except self?
Why you might get asked this:
Tests array manipulation without division and potentially optimizing space complexity by using left/right products.
How to answer:
Calculate prefix products from left, then suffix products from right. The result for nums[i] is prefix[i-1] * suffix[i+1].
Example answer:
Initialize result array. First pass: result[i] stores product of elements to left of i. Second pass: Iterate from right, multiply result[i] by product of elements to right of i.
15. How to generate all subsets of a set?
Why you might get asked this:
A backtracking or bit manipulation problem, fundamental for exploring combinations and power sets.
How to answer:
Use backtracking/recursion. At each step, decide whether to include the current element or not, then recurse for the next.
Example answer:
Initialize res = [[]]. For each num in nums, iterate through existing subsets in res, append num to each, and add the new subsets to res.
16. How to find the median from a data stream?
Why you might get asked this:
Tests data structure knowledge, specifically using two heaps (min-heap and max-heap) to efficiently maintain the median.
How to answer:
Use a max-heap for the lower half and a min-heap for the upper half. Balance them such that their sizes differ by at most one.
Example answer:
Maintain a maxheap for the smaller half and a minheap for the larger half. When adding a number, add to maxheap, then transfer largest from maxheap to minheap. Balance sizes by moving between heaps. Median is top of maxheap or average of tops.
17. Can all courses be finished given prerequisites?
Why you might get asked this:
Graph theory problem involving cycle detection in a directed graph (topological sort or DFS).
How to answer:
Build an adjacency list for courses and their prerequisites. Use Kahn's algorithm (BFS with in-degrees) or DFS with cycle detection.
Example answer:
Build adj list and in-degree array. Add nodes with in-degree 0 to a queue. While queue not empty, dequeue node, decrement in-degree of its neighbors. If neighbor in-degree becomes 0, enqueue. Count processed nodes.
18. How to design and implement an LRU Cache?
Why you might get asked this:
Tests understanding of data structures (hash map and doubly linked list) and object-oriented design for cache management.
How to answer:
Combine a hash map for O(1) key lookup and a doubly linked list to maintain item order (least recently used at tail, most recently used at head).
Example answer:
Use a HashMap for quick access and a DoublyLinkedList for LRU order. get moves node to front. put adds/updates node and moves to front; if capacity exceeded, removes tail.
19. How to find the maximum in each sliding window?
Why you might get asked this:
Advanced sliding window problem often solved with a deque (double-ended queue) to keep track of potential maximums.
How to answer:
Use a deque to store indices. Maintain decreasing order of elements in the deque from front to back. Pop elements outside the window or smaller than current.
Example answer:
Initialize deque and result list. Iterate i from 0 to n-1. Remove elements from back of deque if nums[deque.back()] <= nums[i]. Add i to deque. If deque.front() is out of window, remove. If i >= k-1, add nums[deque.front()] to result.
20. How to find the longest palindromic substring?
Why you might get asked this:
String manipulation, often solvable with dynamic programming or by expanding around centers (odd/even length palindromes).
How to answer:
Iterate through each character as a potential center. Expand outwards to find the longest palindrome. Handle both odd and even length palindromes.
Example answer:
Iterate i from 0 to n-1. For each i, expand around i (odd length palindrome). Also, expand around i and i+1 (even length palindrome). Keep track of the start and max_len found.
21. How to find the Kth largest element in an array?
Why you might get asked this:
Tests sorting, heap (priority queue), or quickselect partitioning algorithm for efficiency.
How to answer:
Use a min-heap of size K. Iterate through array, adding elements. If heap size exceeds K, remove smallest. Heap's top is the Kth largest.
Example answer:
Create a min-heap. Add all elements to the heap. While heap.size() > k, heap.poll(). The heap.peek() is the Kth largest element.
22. How to serialize and deserialize a binary tree?
Why you might get asked this:
Tests tree traversal strategies (e.g., pre-order) and string manipulation for converting a tree to a string and back.
How to answer:
For serialization, use pre-order traversal and represent null nodes with a specific marker (e.g., '#'). For deserialization, parse the string using a queue or recursion.
Example answer:
Serialize: perform pre-order traversal, appending node values and 'null' for nulls to a string, separated by delimiters. Deserialize: split string by delimiter, use a queue. Recursively build tree, taking from queue.
23. How to find the Top K frequent elements?
Why you might get asked this:
Combines hash map for frequency counting and either sorting or a min-heap (priority queue) for top K selection.
How to answer:
First, count frequencies using a hash map. Then, use a min-heap to store (frequency, number) pairs. Keep heap size K.
Example answer:
Count frequencies of each number using a hash map. Create a min-heap of size k. Iterate map entries; add to heap. If heap.size() > k, heap.poll(). Result is heap contents.
24. How to search in a rotated sorted array?
Why you might get asked this:
Tests binary search adaptation in a non-trivial scenario, requiring careful handling of sorted segments.
How to answer:
Use modified binary search. Determine which half of the array is sorted. Check if target lies in the sorted half. Adjust search bounds accordingly.
Example answer:
Perform binary search. Identify if left half (nums[low] to nums[mid]) or right half (nums[mid] to nums[high]) is sorted. Based on target's value, narrow search to the sorted part or the unsorted part.
25. How much rain water can be trapped?
Why you might get asked this:
A classic problem testing array manipulation and two-pointer technique or pre-calculating left/right max heights.
How to answer:
For each bar, water trapped equals min(maxleft, maxright) - height[i]. Pre-calculate maxleft and maxright arrays.
Example answer:
Create leftmax and rightmax arrays. Populate leftmax by iterating from left. Populate rightmax by iterating from right. Iterate again, water += max(0, min(leftmax[i], rightmax[i]) - height[i]).
26. Can a word be found in a grid?
Why you might get asked this:
Backtracking and depth-first search (DFS) on a 2D grid. Common for pathfinding and graph traversal.
How to answer:
Iterate through grid to find first letter. From there, use DFS to explore adjacent cells, marking visited to avoid cycles. Backtrack if path fails.
Example answer:
Iterate grid cells. If board[r][c] == word[0], start DFS from (r, c) with index=0. DFS marks cell visited. For neighbors, recurse dfs(nr, nc, index+1). If no match, unmark and backtrack.
27. How to partition a string into palindromic substrings?
Why you might get asked this:
Backtracking combined with palindrome checking. Tests string manipulation and recursive partitioning.
How to answer:
Use backtracking. At each step, iterate through possible substrings starting from current index. If a substring is a palindrome, add it to current partition and recurse.
Example answer:
Implement a isPalindrome helper. Use a backtracking function backtrack(startindex, currentpartition). Iterate i from startindex to len(s)-1. If s[startindex:i+1] is palindrome, add to current_partition, recurse backtrack(i+1, ...). Remove last for backtracking.
28. How to design a simplified Twitter?
Why you might get asked this:
System design question emphasizing data structures like hash maps, sets, and lists, and understanding feed logic (merge K sorted lists concept).
How to answer:
Use hash maps for user-to-tweets, user-to-followers/followees. Tweets can be stored with a timestamp. Fetching feed involves merging recent tweets from followees.
Example answer:
users map: userId -> list of tweets. follows map: followerId -> set of followeeIds. postTweet: add tweet to user's list. getNewsFeed: retrieve tweets from followed users and self, merge by timestamp. follow/unfollow update follows set.
29. How to find the alien dictionary order?
Why you might get asked this:
Topological sorting on a graph where nodes are characters and edges represent ordering. Tricky graph problem.
How to answer:
Build a directed graph from adjacent words: identify first differing characters to establish order. Then perform topological sort (Kahn's or DFS).
Example answer:
Build adj map (char -> set of chars it precedes) and in-degree map (char -> count of chars preceding it) from words. Initialize queue with 0 in-degree chars. Perform BFS, building result. If result length < unique chars, a cycle exists.
30. How to find minimum meeting rooms required?
Why you might get asked this:
Interval problem, typically solved by sorting events and using a min-heap to track active meetings.
How to answer:
Sort meeting intervals by start times. Use a min-heap to store end times of ongoing meetings. For each new meeting, if heap's top (earliest ending) is earlier than new meeting start, remove. Add new meeting's end time. Max heap size is answer.
Example answer:
Sort meetings by starttime. Initialize minheap (stores end times). Iterate meetings: if heap not empty and meeting.start >= heap.peek(), heap.poll(). heap.offer(meeting.end). maxrooms = max(maxrooms, heap.size()). Return max_rooms.
Other Tips to Prepare for a Hulu LeetCode Interview
Mastering Hulu LeetCode questions requires consistent effort and strategic preparation. Beyond just solving problems, focus on understanding the underlying patterns. As renowned computer scientist Donald Knuth once said, "Science is what we understand well enough to explain to a computer. Art is everything else we do." This emphasizes the importance of clear, precise logic. Practice explaining your thought process aloud, as if you're talking to an interviewer. Consider using tools like Verve AI Interview Copilot (https://vervecopilot.com) to simulate interview conditions and get instant feedback on your coding and communication.
Another crucial tip is to review solutions critically, even if you solve a problem. Look for more optimal approaches or different data structures that could lead to better performance. "The only way to do great work is to love what you do," a quote often attributed to Steve Jobs, reminds us that passion fuels persistence. Engage with the problems, enjoy the challenge, and celebrate small victories. Verve AI Interview Copilot can provide a structured practice environment, helping you track progress and identify areas for improvement. Regularly revisit challenging problems and work on your debugging skills. Leveraging Verve AI Interview Copilot's features can also help refine your verbal communication of complex solutions, which is as important as the code itself.
Frequently Asked Questions
Q1: What programming languages are best for Hulu LeetCode interviews?
A1: Python, Java, and C++ are generally preferred. Choose the language you are most proficient and comfortable with.
Q2: How much time should I dedicate to preparing for Hulu LeetCode?
A2: Dedicate at least 2-3 months for consistent practice, focusing on common patterns and Hulu-specific question types.
Q3: Should I memorize LeetCode solutions?
A3: No, focus on understanding the underlying algorithms and data structures. Memorizing won't help with variations.
Q4: How do I handle new or unseen problems during the interview?
A4: Break down the problem, discuss constraints, clarify edge cases, explain your thought process, and consider different approaches.
Q5: What's the best way to practice without an interviewer?
A5: Use online platforms like Verve AI Interview Copilot to simulate real interviews and receive AI-driven feedback on your performance.
