Coding questions
Walmart Online Assessment
Overview
Detailed public write-ups on the Walmart online test are still hard to find.
What public reports and campus notices usually say (still verify officially):
| Item | Working note |
|---|---|
| Online test name | Walmart Online Assessment (~90 min) |
| Focus areas (metadata) | DSA, aptitude, e-commerce/supply-chain systems. |
| Languages (metadata) | Java, Python, C++ |
| Reported round names | OA (aptitude + coding) → Technical 1 (DSA) → Technical 2 (system design + e-commerce) → HR |
Practice drills
Coding Q1: Binary tree level order
Problem: Given the root of a binary tree, return the level-order traversal (breadth-first) as a list of levels.
Approach: Use a queue. For each level, drain the current queue size, collect values, and enqueue children for the next level.
Complexity: O(n) time, O(n) space
Walmart tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q2: Coin change (min coins)
Problem: Given coin denominations and an amount, return the fewest coins needed to make that amount, or -1 if it is impossible.
Approach: Unbounded knapsack DP: let dp[x] be the minimum coins for amount x. For each coin, update dp[c..amount]. Initialize dp[0] = 0 and the rest to a large sentinel.
Complexity: O(amount × coins)
Walmart tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q3: Binary search
Problem: Given a sorted array of distinct integers and a target, return the index of target or -1 if missing.
Approach: Maintain lo/hi. Compare mid with target and shrink the half that cannot contain it. Careful with overflow-free mid and empty arrays.
Complexity: O(log n) time
Walmart tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
Coding Q4: Move zeros
Problem: Move all zeros in an array to the end while keeping the relative order of non-zero elements.
Approach: Two pointers: write non-zeros toward the front, then fill the remainder with zeros. Or swap zeros as you scan.
Complexity: O(n) time, O(1) space
Walmart tip: Restate the problem, sketch a brute-force idea, then tighten it. Call out edge cases (empty input, single element, overflow) before you write code.
What to do next
- Open the official careers page or your college placement email for Walmart
- Search GeeksforGeeks + Reddit for
Walmart interview experience - Use Faceprep / PrepInsta only if they match your placement email