Quickly brush Uber 2026 OA in 22 minutes: Python problem solving + boundary skills

Rushed recently Uber In 2026 OA, the platform is still CodeSignal, with 4 questions and 70 minutes to complete. To be honest, the questions this time are very familiar to students with a certain foundation. It took me 22 minutes to complete them all. Two of the four questions are almost free. They can be written at a glance and are not difficult at all. To help you practice in advance, I have sorted out the ideas and methods for each question.

Uber 2026 OA Interview Overview

Platform:CodeSignal
Question volume: 4 channels
Time:70 minutes
Difficulty: Above average, but some questions can be completed quickly if you are familiar with them
Inspection point:

1. Binary operations and bit operations
2. Stack and Monotone Stack Techniques
3. Subarray and arrangement judgment
4. String manipulation and exchange matching logic

Generally speaking, Uber OA pays more attention to logical clarity, correctness of ideas and implementation speed. The algorithm is not very difficult, but details are prone to errors.

Q1: Minimum Operations to Reduce Binary Number to Zero

Question description
Given a positive integer n, each operation can add or subtract 2^i (i ≥ 0), find the minimum number of operations to change n to 0.

Problem-solving ideas

• Treat problems as binary
• Process each bit from low to high while maintaining carry
• Current bit value = original bit value + carry
  • If the value is 1: it can be eliminated by direct subtraction, the operand +1, or addition to generate a carry.
  • If the value is 2 (bit 1 + carry 1): carry directly, no increment operation
• Accumulate operands
• End when final carry is 0

Tips

• The most important thing about binary bit processing problem isCarry maintenance
• Be sure to traverse from low to high, otherwise the operand calculation will be wrong.
• You can draw binary bitmaps to quickly understand the operation logic.

Q2: Discounted Price Sum

Question description
The selling price of each item = original price − the price of the first item on the right that is ≤ the current price (if not, it will be sold at the original price). Find the total selling price and the index of the item sold at the original price.

Problem-solving ideas

• Traverse items from right to left
• UseMonotonically increasing stackFind the first item on the right ≤ current price
• Stack empty ⇒ Sold at original price, record index
• The stack is not empty ⇒ Selling price = Original price − Top price of the stack
• Accumulated total selling price
• Output the total selling price and the index of items sold at the original price (ascending order)

Tips

• The monotonic stack is a classic tool for processing "the first qualifying element on the right"
• The core of this type of question isSequence and stack state maintenance
• Pay attention to sorting before outputting the index, otherwise it may be WA

Q3: Balanced Subarray

Question description
For each k (1~n), determine whether there is a subarray that is exactly 1~k.

Problem-solving ideas

• First record the position of each number in the arrangement Pos[value]
• Starting from k = 1, maintain the minimum position interval [L, R] containing the numbers 1~k
  • L = min(pos[1..k])
  • R = max(pos[1..k])
• If R − L + 1 == k, then k is balanced
  • The length of the interval is exactly equal to k, and the value range is 1~k, it must be a permutation
• Otherwise it is not balanced

Tips

• The key is to record the numerical position and maintain the interval minimum and maximum values
• Min/max can be updated cumulatively during traversal without repeated scanning
• This kind of question is very suitable to be implemented with array + index mapping, and the time complexity is O(n)

Q4: Maximum Pairs by Swapping Digits

Question description
Two numbers are counted as a pair if they can be transformed into each other (including equality) by exchanging certain positions of the numbers at most twice. Find the total logarithm.

Problem-solving ideas

1. Different lengths ⇒ Impossible
2. Same length:
   • Convert numbers to strings and sort characters
   • If they are the same after sorting ⇒ they can become each other through several exchanges (counting)
   • If they are different after sorting:
     • Count characters in different positions
     • If the number of different positions is ≤ 4 and characters can be matched in pairs ⇒ can be exchanged twice
3. Implementation steps
   • Group by length first
   • Use a hash table to count the frequency of sorted strings within a group and calculate equal logarithms
   • Check whether two exchange conditions are met for unequal situations

Tips

• Sorting strings can quickly tell if they are likely to become each other by swapping
• Different positions ≤4 are the key judgment conditions
• Hash table grouping statistics can significantly reduce time complexity

FAQ | Uber 2026 OA 1.18 Interview Frequently Asked Questions

Q1: How many questions are there in Uber 2026 OA 1.18? How difficult is it?

Uber 2026 OA 1.18 has a total of 4 questions, including binary addition and subtraction with minimum operands, monotonic stack discount selling price, subarray arrangement judgment and maximum number exchange matching pairs. The difficulty level is medium to high, but most of the question types are common template question types. As long as you are familiar with the CodeSignal platform and Python problem-solving ideas, you can usually complete it quickly.

Q2: How long does it take to complete Uber 2026 OA 1.18?

Based on practical experience, if you are familiar with the question types, all four questions can be completed within 20–30 minutes. It took me 22 minutes to complete the entire set of questions in one go. By properly planning the order of questions and using Python template code, I can save time significantly.

Q3: What are the key points of inspection for Uber 2026 OA?

Mainly examine the following abilities:

• Binary bit operations and carry handling
• Monotone stack application and discount sale price calculation logic
• Subarray arrangement judgment and interval minimum/maximum position maintenance
• String number matching and up to two exchange logic

Also, boundary condition processing, algorithm complexity understanding, and Python implementation capabilities will also be examined.

Q4: What are the advantages of Python in Uber 2026 OA?

Python has a concise syntax, built-in data structures (such as dictionaries, lists, sets) and functions (such as Min, Max, Sorted) is very suitable for handling OA question logic, especially:

• Binary bit operations and carry simulation
• Monotone stack or stack operations
• Index mapping and subarray judgment
• String conversion and hash statistics

Proper use of Python template code can improve completion speed and accuracy.

Q5: Do you have any experience tips to quickly pass Uber 2026 OA?

The experience is summarized as follows:

• Familiar question templates:Binary bit processing, monotonic stack, interval judgment, character exchange matching
• First clarify the logic and then write the code:Make a rough sketch or test with a small sample
• Reasonable time allocation:Do the familiar questions first, leave the difficult ones for last
• Review of boundary conditions:Especially the number of transactions, carry, index length, character matching
• Python template reuse:Prepare functions/tool ​​methods in advance and call them directly

Q6: Will the questions in Uber 2026 OA be repeated?

Based on practical experience, the question types on the CodeSignal platform have a high repetition rate, especially classic template question types like binary operations, monotonic stacks, and subarray arrangements. Practicing these question types in advance and understanding the general solutions and boundary processing methods can greatly improve AC accuracy.

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Jory Wang Amazon Senior Software Development Engineer

Amazon senior engineer, focusing on the research and development of infrastructure core systems, with rich practical experience in system scalability, reliability and cost optimization. Currently focusing on FAANG SDE interview coaching, helping 30+ candidates successfully obtain L5/L6 Offers within one year.

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