
Preparing for Uber coding interview questions can be a challenging yet rewarding endeavor. Uber, a leader in the tech industry, seeks candidates who not only possess strong technical skills but can also apply them to solve complex, real-world problems at scale. This guide aims to demystify the interview process by focusing on the types of questions frequently encountered, covering essential data structures, algorithms, and system design principles. Success in these interviews hinges on a solid understanding of fundamental computer science concepts and the ability to articulate problem-solving approaches clearly and efficiently. By mastering these common Uber coding interview questions, you can significantly boost your chances of joining one of the most innovative companies globally.
What Are Uber Coding Interview Questions?
Uber coding interview questions primarily assess a candidate's proficiency in data structures and algorithms (DSA) as well as system design. These questions are designed to evaluate problem-solving abilities, logical thinking, and coding aptitude. Typical topics include arrays, linked lists, strings, trees, graphs, dynamic programming, and common mathematical problems. For more senior roles, system design questions become critical, testing knowledge of scalable, fault-tolerant, and high-performance architectural principles relevant to Uber's global operations. The difficulty level often ranges from medium to hard on platforms like LeetCode, reflecting the analytical rigor expected from engineers at Uber. Candidates are usually expected to write clean, efficient, and bug-free code during the interview process.
Why Do Interviewers Ask Uber Coding Interview Questions?
Interviewers at Uber ask specific coding interview questions for several key reasons. Firstly, these questions serve as a standardized way to evaluate a candidate's foundational computer science knowledge. They reveal how well you understand data structures like hash maps, linked lists, or trees, and algorithms such as sorting, searching, or dynamic programming. Secondly, they assess your problem-solving methodology. Interviewers want to see how you break down a complex problem into smaller, manageable parts, consider edge cases, and optimize your solution for time and space complexity. Thirdly, these questions gauge your coding proficiency and ability to translate your logic into executable code. Finally, system design questions specifically test your capacity to think at scale, designing robust and scalable solutions, which is crucial for a company like Uber that handles massive amounts of real-time data and user interactions globally.
Find the Missing Number
Two Sum Problem
Maximum Subarray Sum
Move Zeroes to End
Merge Two Sorted Linked Lists
Copy Linked List with Random Pointer
Detect Cycle in Linked List
Find Intersection of Two Linked Lists
Longest Substring Without Repeating Characters
Check Anagrams
Valid Parentheses
Binary Tree Inorder Traversal
Lowest Common Ancestor of a Binary Tree
Check if Binary Tree is Balanced
Number of Islands (Graph DFS/BFS)
Detect Cycle in Directed Graph
Climbing Stairs
Longest Increasing Subsequence
Coin Change Problem
Calculate Power (x^n)
Rotate Image (Matrix rotation)
Sudoku Solver
Permutations of an Array
Design Uber Ride-Sharing System
Design a Distributed Rate Limiter
Design a Real-Time Analytics Dashboard
Validate IP Address
Merge Intervals
Implement LRU Cache
Find Median from Data Stream
Preview List
1. How do you find the missing number in an array?
Why you might get asked this:
This question tests your basic array manipulation skills and ability to use mathematical properties for efficient solutions, a common theme in Uber coding interview questions.
How to answer:
Utilize the sum formula for numbers from 0 to n and subtract the sum of existing array elements. This difference will be the missing number, providing an O(n) solution.
Example answer:
Given numbers 0-3 and array [0, 1, 3]
, the expected sum is (3 * 4) / 2 = 6
. The array sum is 0 + 1 + 3 = 4
. The missing number is 6 - 4 = 2
. This approach works efficiently for large arrays.
2. How do you solve the Two Sum Problem?
Why you might get asked this:
A fundamental problem testing hash table usage for efficient lookups, crucial for optimizing search operations in data structures.
How to answer:
Iterate through the array, storing each number and its complement (target - number) in a hash map. Check if the current number's complement exists in the map.
Example answer:
Put
2
in map. Complement7
.Process
7
. Check if9 - 7 = 2
is in map. Yes. Return indices of2
and7
.
For nums = [2, 7, 11, 15]
and target = 9
:
3. How do you find the maximum subarray sum?
Why you might get asked this:
This question assesses your understanding of dynamic programming or greedy algorithms, specifically Kadane's Algorithm, which is vital for optimizing sequential data processing.
How to answer:
Apply Kadane's Algorithm: maintain two variables, currentmax
(max sum ending at current position) and globalmax
(overall max sum found). Update them iteratively.
Example answer:
For nums = [-2, 1, -3, 4, -1, 2, 1, -5, 4]
:currentmax
resets if it falls below 0. globalmax
updates with the highest current_max
.
Path: [-2] -> [1] -> [1, -3] -> [4] -> [4, -1] -> [4, -1, 2] -> [4, -1, 2, 1]
resulting in 6
.
4. How do you move zeroes to the end of an array?
Why you might get asked this:
Tests in-place array manipulation using two pointers, a common technique for optimizing space complexity in algorithms.
How to answer:
Use two pointers: one to iterate through the array and another to track the position for the next non-zero element. Swap non-zero elements into this position.
Example answer:
Given [0, 1, 0, 3, 12]
:
Pointer i
iterates. Pointer j
tracks non-zero placement.[1, 0, 0, 3, 12]
(1 swapped with 0)[1, 3, 0, 0, 12]
(3 swapped with 0)[1, 3, 12, 0, 0]
(12 swapped with 0)
Result: [1, 3, 12, 0, 0]
.
5. How do you merge two sorted linked lists?
Why you might get asked this:
A classic linked list problem that evaluates your ability to manipulate pointers and handle edge cases while maintaining sorted order.
How to answer:
Use a dummy head node to simplify the merging process. Iterate through both lists, appending the smaller current node to the merged list, and advance the corresponding pointer.
Example answer:
Merge 1->3->5
and 2->4->6
:
Dummy head 0
.
Compare 1
and 2
. Append 1
. List: 0->1
.
Compare 3
and 2
. Append 2
. List: 0->1->2
.
Compare 3
and 4
. Append 3
. List: 0->1->2->3
.
Continue until one list is exhausted, then append the remainder of the other. Result: 0->1->2->3->4->5->6
.
6. How do you copy a linked list with random pointers?
Why you might get asked this:
This advanced linked list problem tests complex pointer manipulation and the efficient use of auxiliary data structures like hash maps or clever in-place modifications.
How to answer:
Use a hash map to store a mapping from original nodes to their corresponding new copies. Iterate twice: once to create nodes and map them, then again to assign next and random pointers.
Example answer:
Create
A'
andB'
. MapA->A'
,B->B'
.For
A'
, setA'.next = B'
andA'.random = map[A.random] = B'
.For
B'
, setB'.next = null
andB'.random = map[B.random] = A'
.
For A->B
with A.random = B
, B.random = A
:
Returns A'
.
7. How do you detect a cycle in a linked list?
Why you might get asked this:
A common linked list question evaluating your understanding of the "fast and slow pointer" technique, critical for cycle detection.
How to answer:
Employ Floyd’s Tortoise and Hare algorithm. Use two pointers, one moving slowly (one step) and one moving fast (two steps). If they meet, a cycle exists.
Example answer:
List 1->2->3->4->2
(cycle at 2):
Slow: 1
, 2
, 3
, 4
, 2
Fast: 1
, 3
, 2
, 4
, 2
They meet at 2
, indicating a cycle. If fast
reaches null
, no cycle.
8. How do you find the intersection of two linked lists?
Why you might get asked this:
This problem assesses your ability to manipulate pointers across two distinct linked lists to find a common meeting point, a useful skill for graph-like structures.
How to answer:
Use two pointers, ptrA
and ptrB
, starting at the heads. When a pointer reaches its list's end, redirect it to the head of the other list. They will meet at the intersection or at null
.
Example answer:
List A: 4->1->8->4->5
List B: 5->6->1->8->4->5
Pointers will traverse their own lists. When ptrA
reaches null
, it goes to B
's head. When ptrB
reaches null
, it goes to A
's head. Eventually, both will arrive at 8
(the intersection node) at the same time.
9. How do you find the longest substring without repeating characters?
Why you might get asked this:
A classic string manipulation problem using the sliding window technique, which is crucial for optimizing substring-related queries.
How to answer:
Use a sliding window (defined by left
and right
pointers) and a hash set to track characters within the current window. Expand right
, shrinking left
if a duplicate is found.
Example answer:
For s = "abcabcbb"
:a
(max=1)ab
(max=2)abc
(max=3)abca
(duplicate a
, move left
past first a
) -> bca
(max=3)bcab
(duplicate b
, move left
past first b
) -> cab
(max=3)cabc
(duplicate c
, move left
past first c
) -> abc
(max=3)
Result: 3.
10. How do you check if two strings are anagrams?
Why you might get asked this:
Tests basic string processing and efficient character counting, often demonstrating a preference for hash map or array-based solutions over sorting.
How to answer:
Use a character count array (size 26 for lowercase English letters) or a hash map. Increment counts for the first string, decrement for the second. If all counts are zero, they are anagrams.
Example answer:
s1 = "listen"
, s2 = "silent"
:
Count array: l:1, i:1, s:1, t:1, e:1, n:1
for s1
.
Decrement for s2
: s:0, i:0, l:0, e:0, n:0, t:0
.
All counts are zero, so they are anagrams.
11. How do you validate parentheses in a string?
Why you might get asked this:
Assesses stack data structure usage for matching opening and closing characters, a common pattern in parsing and expression evaluation.
How to answer:
Iterate through the string. Push opening brackets ( { [
onto a stack. When a closing bracket ) } ]
is encountered, pop from the stack and check if it matches the corresponding opening bracket.
Example answer:
For s = "({[]})"
:(
: push (
. Stack: [
{
: push {
. Stack: [
, {
[
: push [
. Stack: [
, {
, [
]
: pop [
. Match. Stack: [
, {
}
: pop {
. Match. Stack: [
)
: pop (
. Match. Stack: []
Stack is empty at the end, so valid.
12. How do you perform an inorder traversal of a binary tree?
Why you might get asked this:
A fundamental tree traversal method that assesses your understanding of recursion or iterative stack-based approaches.
How to answer:
Recursively: traverse left subtree, visit current node, then traverse right subtree. Iteratively: use a stack, pushing nodes and moving left until null, then pop, visit, and move right.
Example answer:
Tree:
Recursive: inorder(2) -> visit 4 -> inorder(5)
.inorder(2)
: inorder(null) -> visit 2 -> inorder(null)
.
Result: 2, 4, 5
.
13. How do you find the lowest common ancestor (LCA) of a binary tree?
Why you might get asked this:
Tests your recursive thinking and ability to navigate tree structures to find common ancestry, a common problem in hierarchical data.
How to answer:
Recursively search for both nodes (p
and q
). If a node's left and right subtrees both contain one of p
or q
, then that node is the LCA. If the node itself is p
or q
, it could be the LCA.
Example answer:
Tree: 3->(5,1)
where 5->(6,2)
and 1->(0,8)
. Find LCA of 5
and 1
.lca(root, 5, 1)
:
Left subtree (5
): returns 5
. Right subtree (1
): returns 1
.
Since both left and right return non-null and distinct values, root
(3
) is the LCA.
14. How do you check if a binary tree is balanced?
Why you might get asked this:
Evaluates recursive tree traversal and the ability to pass information (like height) back up the call stack to make decisions.
How to answer:
Perform a post-order DFS. Each node returns its height. If at any point the height difference between left and right children is greater than 1, or if a child subtree is unbalanced, return -1 (indicating unbalanced).
Example answer:
Check balance for a node: height = max(leftheight, rightheight) + 1
.
If abs(leftheight - rightheight) > 1
, return -1.null
node has height 0.
A tree like 1->(2, null), 2->(3, null)
is unbalanced. 3
has height 1, 2
has height 2, 1
has height 3. abs(3-0) > 1
at root 1
means unbalanced.
15. How do you count the number of islands in a grid?
Why you might get asked this:
A standard graph traversal problem (DFS or BFS) that assesses connectivity analysis in a 2D grid, relevant for map-based applications.
How to answer:
Iterate through the grid. When a '1' (land) is found, increment island count and then start a DFS/BFS from that cell to mark all connected '1's as visited ('0').
Example answer:
Encounter
(0,0)
'1'. Count = 1. DFS from(0,0)
marks(0,0),(0,1),(1,0),(1,1)
as visited.Next
(0,2)
is '0'.Encounter
(2,2)
'1'. Count = 2. DFS from(2,2)
marks(2,2)
visited.Encounter
(3,3)
'1'. Count = 3. DFS from(3,3)
marks(3,3),(3,4)
visited.
Grid:11000
11000
00100
00011
Total islands: 3.
16. How do you detect a cycle in a directed graph?
Why you might get asked this:
A crucial graph algorithm problem testing DFS with state tracking (visiting, visited) to identify back edges, essential for dependency analysis.
How to answer:
Use DFS with three states for each node: unvisited
, visiting
(currently in recursion stack), and visited
(finished processing). A cycle is detected if DFS encounters a node in the visiting
state.
Example answer:
DFS from
A
: MarkA
asvisiting
.Visit
B
: MarkB
asvisiting
.Visit
C
: MarkC
asvisiting
.Visit
A
fromC
:A
isvisiting
, so cycle detected.
Graph: A->B, B->C, C->A
If C
instead pointed to D
, C
would be marked visited
before returning.
17. How do you solve the Climbing Stairs problem?
Why you might get asked this:
A classic dynamic programming problem that maps directly to the Fibonacci sequence, assessing your ability to identify recursive patterns and optimize with memoization.
How to answer:
This is a Fibonacci sequence. The number of ways to climb n
stairs is the sum of ways to climb n-1
stairs and n-2
stairs. Use DP (bottom-up array or two variables) to store results.
Example answer:
n=1
: 1 way (1
)n=2
: 2 ways (1+1
, 2
)n=3
: ways(2) + ways(1) = 2 + 1 = 3
(1+1+1
, 1+2
, 2+1
)n=4
: ways(3) + ways(2) = 3 + 2 = 5
This is fib(n+1)
.
18. How do you find the longest increasing subsequence?
Why you might get asked this:
A more complex dynamic programming problem requiring careful state definition and optimization, sometimes with binary search, which is a good test of advanced algorithmic thinking.
How to answer:
DP approach: dp[i]
stores the length of the LIS ending at index i
. Iterate j
from 0
to i-1
. If nums[i] > nums[j]
, dp[i] = max(dp[i], dp[j] + 1)
.
Optimized with binary search: Maintain an tails
array where tails[i]
is the smallest tail of all increasing subsequences of length i+1
. Use binary search to find insertion point.
Example answer:
nums = [10, 9, 2, 5, 3, 7, 101, 18]
DP table:dp[0]=1
for 10
dp[1]=1
for 9
dp[2]=1
for 2
dp[3]=2
for 5
(from 2
)dp[4]=2
for 3
(from 2
)dp[5]=3
for 7
(from 2,5
or 2,3
)dp[6]=4
for 101
(from 2,5,7
or 2,3,7
)dp[7]=4
for 18
(from 2,5,7
or 2,3,7
)
Max DP value is 4.
19. How do you solve the Coin Change Problem?
Why you might get asked this:
A classic DP problem testing optimization for minimum counts, applicable to resource allocation or scheduling scenarios.
How to answer:
Use bottom-up DP. dp[i]
represents the minimum number of coins to make amount i
. Initialize dp[0]=0
and others to infinity. Iterate from 1
to amount
, and for each coin
, dp[i] = min(dp[i], dp[i - coin] + 1)
.
Example answer:
coins = [1, 2, 5]
, amount = 11
dp
array of size 12 (for 0 to 11), initially all infinity
except dp[0]=0
.dp[1]=1
(1 coin of 1)dp[2]=1
(1 coin of 2)dp[3]=2
(from dp[3-1]+1
or dp[3-2]+1
)
...dp[11]
will be min(dp[11-1]+1, dp[11-2]+1, dp[11-5]+1)
dp[11] = min(dp[10]+1, dp[9]+1, dp[6]+1)
dp[11] = min(2+1, 2+1, 2+1) = 3
(e.g., 5+5+1).
20. How do you calculate power (x^n) efficiently?
Why you might get asked this:
Tests your understanding of mathematical optimization through divide and conquer, crucial for handling large exponents without overflow or timeouts.
How to answer:
Use fast exponentiation (exponentiation by squaring). If n
is even, x^n = (x^(n/2))^2
. If n
is odd, x^n = x * (x^((n-1)/2))^2
. Handle negative n
by 1/x^(-n)
.
Example answer:
x = 2, n = 10
pow(2, 10) = pow(2, 5)^2
pow(2, 5) = 2 * pow(2, 2)^2
pow(2, 2) = pow(2, 1)^2
pow(2, 1) = 2 pow(2, 0)^2 = 2 1^2 = 2
Backtrack: pow(2, 2) = 2^2 = 4
pow(2, 5) = 2 4^2 = 2 16 = 32
pow(2, 10) = 32^2 = 1024
.
21. How do you rotate an image (NxN matrix) by 90 degrees?
Why you might get asked this:
A common matrix manipulation problem that requires in-place transformation, testing your ability to swap elements and handle boundaries.
How to answer:
First, transpose the matrix (swap matrix[i][j]
with matrix[j][i]
). Then, reverse each row. This rotates the matrix 90 degrees clockwise in-place.
Example answer:
Original (2x2):1 2
3 4
Transpose:1 3
2 4
Reverse rows:
Row 1: 3 1
Row 2: 4 2
Result:3 1
4 2
22. How do you solve a Sudoku puzzle?
Why you might get asked this:
A classic backtracking problem that tests your ability to explore possibilities, manage state, and efficiently prune invalid paths.
How to answer:
Use a recursive backtracking approach. Find an empty cell. Try placing numbers 1-9. For each number, check if it's valid in its row, column, and 3x3 subgrid. If valid, recursively call the function for the next empty cell. If no number works, backtrack.
Example answer:
Given a partially filled Sudoku board: 3 | 2 | 6
4 | | _ 1
9 | 6 | 7
...
Try 1
at (0,0)
. Is 1
valid? Check row 0, col 0, 3x3 block. If yes, place 1
. Move to (0,1)
.
If 1
is invalid, try 2
, etc. If no number works at (0,0)
, backtrack (remove 1
and return false
).
23. How do you generate all permutations of an array?
Why you might get asked this:
Tests recursive thinking and backtracking for combinatorial problems, foundational for many search and optimization algorithms.
How to answer:
Use a recursive backtracking function. For each position, iterate through the available (unvisited) numbers. Place an available number, mark it visited, then recurse for the next position. After the recursive call, unmark the number (backtrack).
Example answer:
Choose
1
. Remaining:[2, 3]
. Call for[2, 3]
.
nums = [1, 2, 3]
a. Choose 2
. Remaining: [3]
. Call for [3]
.
i. Choose 3
. Remaining: []
. Add [1, 2, 3]
to result. Return.
b. Backtrack. Choose 3
. Remaining: [2]
. Call for [2]
.
i. Choose 2
. Remaining: []
. Add [1, 3, 2]
to result. Return.
...and so on for starting with 2
and 3
.
24. How would you design an Uber Ride-Sharing System?
Why you might get asked this:
A cornerstone system design question for Uber, assessing your ability to design scalable, real-time, and location-based services, crucial for a company of its nature.
How to answer:
Discuss core components: user services, driver services, matching service, real-time location tracking, surge pricing, payment gateway, notification service. Focus on scalability (sharding, load balancing), data consistency (ACID vs. BASE), and latency.
Example answer:
Key services: User/Driver Management (profiles, authentication), Map Service (GPS, routing), Dispatch Service (matching riders/drivers), Pricing (dynamic/surge), Payment, Notification. Data storage: geo-spatial database for locations, relational for user/driver info, NoSQL for real-time ride data. APIs for communication. Consider message queues for asynchronous tasks like notifications.
25. How would you design a Distributed Rate Limiter?
Why you might get asked this:
Tests your understanding of distributed systems challenges, concurrency, and different rate limiting algorithms, essential for preventing abuse and ensuring system stability.
How to answer:
Explain different algorithms: Token Bucket, Leaky Bucket, Fixed Window Counter, Sliding Log, Sliding Window Counter. For distributed, discuss consistency using Redis (incr/expire), synchronization using locks or distributed consensus, and edge cases like clock skew.
Example answer:
For a Token Bucket: each user gets a bucket of tokens, refilled at a fixed rate. Requests consume tokens. If bucket empty, request rejected. Distributedly, use Redis to store bucket state (tokens, last refill time) for each user/API endpoint. Atomically decrement tokens. Consider a centralized Redis or sharding.
26. How would you design a Real-Time Analytics Dashboard?
Why you might get asked this:
Assesses data engineering and system design skills for processing and visualizing large volumes of data in real-time, critical for operational insights at Uber.
How to answer:
Describe the data pipeline: data ingestion (Kafka/Kinesis from ride-events, etc.), stream processing (Flink/Spark Streaming for aggregations), data storage (columnar databases like Druid, OLAP databases), and visualization layer. Emphasize low latency, fault tolerance, and data freshness.
Example answer:
Data Ingestion: Ride events (start, end, location updates, payments) sent to Kafka.
Stream Processing: Kafka streams processed by Apache Flink/Spark Streaming for real-time aggregations (e.g., active rides by city, revenue per minute).
Data Storage: Aggregated metrics stored in a fast querying data store (e.g., Apache Druid, ClickHouse) optimized for time-series queries.
Dashboard: Web application polls data store or uses WebSockets for real-time updates.
27. How do you validate an IP Address?
Why you might get asked this:
A string parsing problem that tests attention to detail, handling multiple formats (IPv4/IPv6), and edge cases.
How to answer:
Split the string by delimiters (.
for IPv4, :
for IPv6). Validate each segment based on the rules: for IPv4, 4 segments, each 0-255, no leading zeros. For IPv6, 8 segments, 1-4 hex chars, no leading/trailing colons.
Example answer:
IPv4 192.168.1.1
: Split by .
. Check 192
, 168
, 1
, 1
are valid integers between 0-255 and have no leading zeros unless it's just '0'.
IPv6 2001:0db8:85a3:0000:0000:8a2e:0370:7334
: Split by :
. Check 8 segments, each 1-4 hex digits.
Handle invalid number of segments or invalid characters.
28. How do you merge overlapping intervals?
Why you might get asked this:
A common array/list problem requiring sorting and careful interval management, useful for scheduling or time-based data.
How to answer:
Sort the intervals by their start times. Iterate through the sorted intervals, merging the current interval with the last merged interval if they overlap. Otherwise, add the current interval to the result.
Example answer:
Sorted (already is).
Start with
[1,3]
. Result:[[1,3]]
.Next
[2,6]
. Overlaps with[1,3]
. Merge to[1,6]
. Result:[[1,6]]
.Next
[8,10]
. Does not overlap[1,6]
. Add[8,10]
. Result:[[1,6],[8,10]]
.Next
[15,18]
. Does not overlap[8,10]
. Add[15,18]
. Result:[[1,6],[8,10],[15,18]]
.
intervals = [[1,3],[2,6],[8,10],[15,18]]
29. How do you implement an LRU Cache?
Why you might get asked this:
A classic design problem testing your ability to combine a hash map and a double linked list for efficient O(1) average time complexity for put/get operations.
How to answer:
Use a hash map to store key -> Node
mappings for O(1) access. Use a double linked list to maintain the order of usage (most recently used at head, least recently used at tail). On get
, move node to head. On put
, add new node to head; if capacity exceeded, remove tail node.
Example answer:
Cache capacity 2.put(1, 10)
: map={1->Node1}
, DLL=Node1
put(2, 20)
: map={1->Node1, 2->Node2}
, DLL=Node2<->Node1
get(1)
: Access Node1. Move Node1 to head. map={1->Node1, 2->Node2}
, DLL=Node1<->Node2
. Returns 10.put(3, 30)
: Capacity exceeded. Remove LRU (Node2). map={1->Node1, 3->Node3}
, DLL=Node3<->Node1
.
30. How do you find the median from a data stream?
Why you might get asked this:
Tests your ability to use two heaps (min-heap and max-heap) to maintain a dynamically changing median, essential for real-time data analysis.
How to answer:
Maintain two heaps: a max-heap
for the lower half of numbers and a min-heap
for the upper half. Ensure max-heap.size() >= min-heap.size()
and max-heap.top() <= min-heap.top()
. Add numbers by putting into max-heap, then balance by moving top to min-heap if needed. Rebalance if sizes differ too much.
Example answer:
Add
1
:maxheap=[1]
,minheap=[]
. Median = 1.Add
2
:maxheap=[1]
,minheap=[2]
. Balance: push1
tominheap
.maxheap=[]
,minheap=[1,2]
. Wait,maxheap
needs1
. Push2
tomaxheap
.maxheap=[2]
,minheap=[]
. Then1
gets pushed tomaxheap
.maxheap=[2,1]
. Balance:1
tominheap
.maxheap=[2]
,minheap=[1]
. Median =(1+2)/2 = 1.5
. No,maxheap
holds smaller half,minheap
larger half.Add
1
:max_heap = [1]
. Median = 1.Add
2
: Push2
tominheap
.maxheap = [1]
,minheap = [2]
. Balance sizes:maxheap
pop1
, push1
tominheap
.maxheap = []
,min_heap = [1, 2]
. This isn't right.
Stream: 1, 2, 3, 4
Let's restart the example.
Correct: maxheap
for smallest of largest half, minheap
for largest of smallest half.
Add 1
: maxheap.add(1)
. maxheap=[1]
. min_heap=[]
. Median = 1.
Add 2
: minheap.add(2)
. maxheap=[1]
, minheap=[2]
. Balance sizes. minheap
size > maxheap
. Pop 2
from minheap
to maxheap
. maxheap=[2,1]
, min_heap=[]
. Median = 2.
Add 3
: maxheap.add(3)
. maxheap=[3,2,1]
. minheap=[]
. Balance sizes. Pop 1
to minheap
. maxheap=[3,2]
, minheap=[1]
. Median = 2.
Add 4
: minheap.add(4)
. maxheap=[3,2]
, minheap=[1,4]
. Balance maxheap
size (2
) and min_heap
size (2
). Median = (2+3)/2 = 2.5
.
Other Tips to Prepare for an Uber Coding Interview
Preparing for Uber coding interview questions requires more than just solving problems; it demands a holistic approach to skill development and interview strategy. As tech leader Satya Nadella once said, "Our industry does not respect tradition, it only respects innovation." This means staying current with best practices and continuously refining your problem-solving toolkit. Firstly, thoroughly practice on platforms like LeetCode, focusing on problems tagged "Uber" and related to data structures and algorithms. Pay attention to time and space complexity and aim for optimal solutions. Secondly, for system design questions, understand the fundamental building blocks of large-scale distributed systems, including concepts like scalability, consistency, availability, and fault tolerance.
To truly excel, consider leveraging an AI-powered tool. The Verve AI Interview Copilot can be an invaluable resource, offering real-time feedback and personalized coaching, mimicking the actual interview environment. As legendary investor Warren Buffett states, "The best investment you can make is in yourself." Practicing with a tool like Verve AI Interview Copilot allows you to refine your communication and thought processes under pressure. Use Verve AI Interview Copilot to simulate various Uber coding interview questions, ensuring you articulate your solutions clearly and concisely. Additionally, familiarize yourself with Uber's technology stack, usually Python, Java, or C++, and its microservices architecture. Reviewing successful interview experiences and common pitfalls can also provide significant insights. For more practice, visit https://vervecopilot.com.
Frequently Asked Questions
Q1: What programming languages are best for Uber coding interviews?
A1: Python, Java, and C++ are commonly used and accepted for Uber coding interviews. Choose the language you are most proficient in.
Q2: How much time should I allocate for Uber interview preparation?
A2: Most candidates spend 2-4 months preparing, focusing on daily practice in data structures, algorithms, and system design.
Q3: Are behavioral questions important for Uber interviews?
A3: Yes, behavioral questions are crucial. Prepare to discuss your experience, teamwork, and how you handle challenges using the STAR method.
Q4: What is the typical structure of an Uber coding interview?
A4: Typically, it involves an initial phone screen, followed by multiple onsite rounds covering coding (DSA), system design, and behavioral aspects.
Q5: Should I memorize solutions to problems?
A5: No, focus on understanding the underlying data structures, algorithms, and problem-solving patterns rather than memorizing specific solutions.