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Walmart Labs DSA Interview Questions

143 curated coding interview questions directly asked in Walmart Labs technical rounds, sorted by frequency with recency and difficulty diagnostics.

⚡ Open Interactive Tracker (143 Problems) 🔥 Must-Solve Problem Pool 🏢 All Companies Directory

143 Total Questions

21 (15%) Easy Problems

98 (69%) Medium Problems

24 (17%) Hard Problems

🔥 Most Tested Topics:

Arrays (47)Core DSA (35)Strings (25)Trees (13)Backtracking (9)

📂 Sourced Datasets:

Last 30 daysLast 3 monthsLast 6 monthsAll questionsOlder than 6 months

Showing 143 of 143 displayed

ID	Problem	Difficulty	Topic	Pattern	Acceptance	Frequency	Recency
870	Advantage Shuffle	Medium	Core DSA	Implementation / Reasoning	54.6%	100.0%	30d
200	Number of Islands	Medium	Graphs	BFS / DFS / Topological Sort	64.4%	100.0%	3m
3	Longest Substring Without Repeating Characters	Medium	Strings; Trees	Hashing / Sliding Window; DFS / BFS; Sliding Window	39.1%	100.0%	all
20	Valid Parentheses	Easy	Strings	Hashing / Sliding Window	44.2%	100.0%	all
146	LRU Cache	Medium	Design	Data Structure Design	47.4%	100.0%	all
560	Subarray Sum Equals K	Medium	Arrays	Sorting / Prefix / Scan	47.3%	87.5%	6m
22	Generate Parentheses	Medium	Strings	Hashing / Sliding Window	78.7%	87.5%	all
33	Search in Rotated Sorted Array	Medium	Arrays; Binary Search	Sorting / Prefix / Scan; Binary Search	44.9%	87.5%	all
1977	Number of Ways to Separate Numbers	Hard	Core DSA	Implementation / Reasoning	21.7%	87.5%	all
2072	The Winner University	Easy	Core DSA	Implementation / Reasoning	75.6%	87.5%	all
2179	Count Good Triplets in an Array	Hard	Arrays	Sorting / Prefix / Scan	65.5%	87.5%	all
2406	Divide Intervals Into Minimum Number of Groups	Medium	Arrays	Sorting / Prefix / Scan	63.6%	87.5%	all
2449	Minimum Number of Operations to Make Arrays Similar	Hard	Arrays	Sorting / Prefix / Scan	61.5%	87.5%	all
2541	Minimum Operations to Make Array Equal II	Medium	Arrays	Sorting / Prefix / Scan	33.2%	87.5%	all
2071	Maximum Number of Tasks You Can Assign	Hard	Arrays	Sorting / Prefix / Scan	50.0%	87.5%	all
876	Middle of the Linked List	Easy	Linked List	Two Pointers	81.8%	87.5%	all
3005	Count Elements With Maximum Frequency	Easy	Arrays	Sorting / Prefix / Scan	79.8%	87.5%	all
3090	Maximum Length Substring With Two Occurrences	Easy	Arrays; Strings; Trees	Sorting / Prefix / Scan; Hashing / Sliding Window; DFS / BFS	65.5%	87.5%	all
1238	Circular Permutation in Binary Representation	Medium	Backtracking	Backtracking	72.7%	87.5%	all
3179	Find the N-th Value After K Seconds	Medium	Core DSA	Implementation / Reasoning	53.9%	87.5%	all
1486	XOR Operation in an Array	Easy	Arrays	Sorting / Prefix / Scan	87.6%	87.5%	all
1	Two Sum	Easy	Arrays	Sorting / Prefix / Scan; Two Pointers	57.5%	75.0%	3m
121	Best Time to Buy and Sell Stock	Easy	Core DSA	Implementation / Reasoning	56.8%	75.0%	3m
75	Sort Colors	Medium	Arrays	Sorting / Prefix / Scan	69.6%	75.0%	3m
56	Merge Intervals	Medium	Arrays	Sorting / Prefix / Scan	51.8%	75.0%	3m
567	Permutation in String	Medium	Strings; Backtracking	Hashing / Sliding Window; Sliding Window; Backtracking	48.9%	75.0%	6m
198	House Robber	Medium	Dynamic Programming	State Transition	53.2%	75.0%	6m
5	Longest Palindromic Substring	Medium	Strings; Trees	Hashing / Sliding Window; DFS / BFS	37.8%	75.0%	6m
460	LFU Cache	Hard	Design	Data Structure Design	49.2%	75.0%	6m
207	Course Schedule	Medium	Graphs	BFS / DFS / Topological Sort	51.4%	75.0%	6m
49	Group Anagrams	Medium	Strings	Hashing / Sliding Window	72.6%	75.0%	6m
42	Trapping Rain Water	Hard	Core DSA	Two Pointers	67.4%	75.0%	6m
15	3Sum	Medium	Arrays	Sorting / Prefix / Scan	39.1%	75.0%	6m
713	Subarray Product Less Than K	Medium	Arrays	Sorting / Prefix / Scan	54.3%	75.0%	6m
11	Container With Most Water	Medium	Core DSA	Two Pointers	60.0%	75.0%	all
39	Combination Sum	Medium	Arrays; Backtracking	Sorting / Prefix / Scan; Backtracking	76.5%	75.0%	all
128	Longest Consecutive Sequence	Medium	Core DSA	Implementation / Reasoning	47.1%	75.0%	all
139	Word Break	Medium	Strings; Dynamic Programming	Hashing / Sliding Window; State Transition	49.5%	75.0%	all
215	Kth Largest Element in an Array	Medium	Arrays; Heap	Sorting / Prefix / Scan; Priority Queue	68.9%	75.0%	all
322	Coin Change	Medium	Dynamic Programming	State Transition	48.4%	75.0%	all
716	Max Stack	Hard	Stack / Queue	Monotonic Stack / Simulation	45.9%	75.0%	all
300	Longest Increasing Subsequence	Medium	Dynamic Programming	State Transition	59.4%	75.0%	all
3696	Maximum Distance Between Unequal Words in Array I	Easy	Arrays; Strings	Sorting / Prefix / Scan; Hashing / Sliding Window	83.0%	75.0%	all
4	Median of Two Sorted Arrays	Hard	Arrays; Heap	Sorting / Prefix / Scan; Priority Queue	46.6%	62.5%	all
23	Merge k Sorted Lists	Hard	Arrays; Linked List; Heap	Sorting / Prefix / Scan; Two Pointers; Priority Queue	59.6%	62.5%	all
25	Reverse Nodes in k-Group	Hard	Trees; Linked List	DFS / BFS; Two Pointers	66.1%	62.5%	all
36	Valid Sudoku	Medium	Strings; Backtracking	Hashing / Sliding Window; Backtracking	64.5%	62.5%	all
53	Maximum Subarray	Medium	Arrays	Sorting / Prefix / Scan	53.3%	62.5%	all
54	Spiral Matrix	Medium	Arrays	Sorting / Prefix / Scan	56.8%	62.5%	all
67	Add Binary	Easy	Core DSA	Implementation / Reasoning	58.1%	62.5%	all
103	Binary Tree Zigzag Level Order Traversal	Medium	Trees	DFS / BFS	63.7%	62.5%	all
199	Binary Tree Right Side View	Medium	Trees	DFS / BFS	70.2%	62.5%	all
44	Wildcard Matching	Hard	Core DSA	Implementation / Reasoning	32.0%	62.5%	all
283	Move Zeroes	Easy	Core DSA	Two Pointers	63.8%	62.5%	all
347	Top K Frequent Elements	Medium	Heap	Priority Queue	66.4%	62.5%	all
387	First Unique Character in a String	Easy	Strings	Hashing / Sliding Window	65.5%	62.5%	all
90	Subsets II	Medium	Backtracking	Backtracking	61.3%	62.5%	all
6	Zigzag Conversion	Medium	Core DSA	Implementation / Reasoning	54.2%	62.5%	all
2461	Maximum Sum of Distinct Subarrays With Length K	Medium	Arrays	Sorting / Prefix / Scan	43.0%	62.5%	all
407	Trapping Rain Water II	Hard	Core DSA	Two Pointers	64.1%	62.5%	all
12	Integer to Roman	Medium	Strings	Hashing / Sliding Window	71.0%	62.5%	all
647	Palindromic Substrings	Medium	Strings; Trees	Hashing / Sliding Window; DFS / BFS	72.8%	62.5%	all
295	Find Median from Data Stream	Hard	Heap	Priority Queue	54.5%	62.5%	all
362	Design Hit Counter	Medium	Design	Data Structure Design	69.7%	62.5%	all
994	Rotting Oranges	Medium	Core DSA	Implementation / Reasoning	58.7%	62.5%	all
498	Diagonal Traverse	Medium	Core DSA	Implementation / Reasoning	67.2%	62.5%	all
1329	Sort the Matrix Diagonally	Medium	Arrays	Sorting / Prefix / Scan	83.2%	62.5%	all
106	Construct Binary Tree from Inorder and Postorder Traversal	Medium	Trees	DFS / BFS	68.7%	62.5%	all
41	First Missing Positive	Hard	Arrays	Sorting / Prefix / Scan	42.9%	50.0%	all
74	Search a 2D Matrix	Medium	Arrays; Binary Search	Sorting / Prefix / Scan; Binary Search	53.9%	50.0%	all
76	Minimum Window Substring	Hard	Arrays; Strings; Trees	Sorting / Prefix / Scan; Hashing / Sliding Window; DFS / BFS; Sliding Window	47.5%	50.0%	all
79	Word Search	Medium	Strings; Binary Search	Hashing / Sliding Window; Binary Search	47.4%	50.0%	all
84	Largest Rectangle in Histogram	Hard	Core DSA	Implementation / Reasoning	49.9%	50.0%	all
91	Decode Ways	Medium	Dynamic Programming	State Transition	38.0%	50.0%	all
122	Best Time to Buy and Sell Stock II	Medium	Core DSA	Implementation / Reasoning	71.1%	50.0%	all
138	Copy List with Random Pointer	Medium	Linked List	Two Pointers	62.9%	50.0%	all
155	Min Stack	Medium	Stack / Queue	Monotonic Stack / Simulation	58.2%	50.0%	all
189	Rotate Array	Medium	Arrays	Sorting / Prefix / Scan	44.9%	50.0%	all
210	Course Schedule II	Medium	Graphs	BFS / DFS / Topological Sort	55.5%	50.0%	all
739	Daily Temperatures	Medium	Stack / Queue	Monotonic Stack / Simulation	68.7%	50.0%	all
1143	Longest Common Subsequence	Medium	Core DSA	Implementation / Reasoning	59.2%	50.0%	all
55	Jump Game	Medium	Greedy	Greedy	40.9%	50.0%	all
57	Insert Interval	Medium	Arrays	Sorting / Prefix / Scan	45.2%	50.0%	all
1249	Minimum Remove to Make Valid Parentheses	Medium	Arrays; Strings	Sorting / Prefix / Scan; Hashing / Sliding Window	71.5%	50.0%	all
120	Triangle	Medium	Core DSA	Implementation / Reasoning	59.9%	50.0%	all
153	Find Minimum in Rotated Sorted Array	Medium	Arrays; Binary Search	Sorting / Prefix / Scan; Binary Search	54.7%	50.0%	all
490	The Maze	Medium	Core DSA	Implementation / Reasoning	60.4%	50.0%	all
1209	Remove All Adjacent Duplicates in String II	Medium	Arrays; Strings	Sorting / Prefix / Scan; Hashing / Sliding Window	61.3%	50.0%	all
735	Asteroid Collision	Medium	Core DSA	Implementation / Reasoning	47.9%	50.0%	all
19	Remove Nth Node From End of List	Medium	Trees; Linked List	DFS / BFS; Two Pointers	51.6%	50.0%	all
73	Set Matrix Zeroes	Medium	Arrays	Sorting / Prefix / Scan	62.9%	50.0%	all
402	Remove K Digits	Medium	Core DSA	Implementation / Reasoning	36.9%	50.0%	all
556	Next Greater Element III	Medium	Stack / Queue	Monotonic Stack / Simulation	35.3%	50.0%	all
31	Next Permutation	Medium	Backtracking	Backtracking	45.3%	50.0%	all
14	Longest Common Prefix	Easy	Core DSA	Implementation / Reasoning	47.6%	37.5%	all
50	Pow(x, n)	Medium	Core DSA	Implementation / Reasoning	38.7%	37.5%	all
116	Populating Next Right Pointers in Each Node	Medium	Trees	DFS / BFS	67.2%	37.5%	all
238	Product of Array Except Self	Medium	Arrays	Sorting / Prefix / Scan	68.9%	37.5%	all
341	Flatten Nested List Iterator	Medium	Linked List; Design	Two Pointers; Data Structure Design	65.7%	37.5%	all
416	Partition Equal Subset Sum	Medium	Arrays; Dynamic Programming	Sorting / Prefix / Scan; State Transition	49.5%	37.5%	all
48	Rotate Image	Medium	Arrays	Sorting / Prefix / Scan	80.1%	37.5%	all
451	Sort Characters By Frequency	Medium	Arrays; Strings	Sorting / Prefix / Scan; Hashing / Sliding Window	75.3%	37.5%	all
227	Basic Calculator II	Medium	Stack / Queue	Monotonic Stack / Simulation	46.9%	37.5%	all
525	Contiguous Array	Medium	Arrays	Sorting / Prefix / Scan	51.3%	37.5%	all
162	Find Peak Element	Medium	Binary Search	Binary Search	47.0%	37.5%	all
373	Find K Pairs with Smallest Sums	Medium	Arrays	Sorting / Prefix / Scan	41.9%	37.5%	all
665	Non-decreasing Array	Medium	Arrays	Sorting / Prefix / Scan	25.5%	37.5%	all
81	Search in Rotated Sorted Array II	Medium	Arrays; Binary Search	Sorting / Prefix / Scan; Binary Search	40.1%	37.5%	all
7	Reverse Integer	Medium	Core DSA	Implementation / Reasoning	31.9%	37.5%	all
40	Combination Sum II	Medium	Arrays; Backtracking	Sorting / Prefix / Scan; Backtracking	59.5%	37.5%	all
730	Count Different Palindromic Subsequences	Hard	Core DSA	Implementation / Reasoning	47.8%	37.5%	all
92	Reverse Linked List II	Medium	Linked List	Two Pointers	51.5%	37.5%	all
152	Maximum Product Subarray	Medium	Arrays	Sorting / Prefix / Scan	36.4%	37.5%	all
2423	Remove Letter To Equalize Frequency	Easy	Strings	Hashing / Sliding Window	19.4%	37.5%	all
1823	Find the Winner of the Circular Game	Medium	Core DSA	Implementation / Reasoning	82.2%	37.5%	all
253	Meeting Rooms II	Medium	Greedy	Greedy	52.7%	37.5%	all
78	Subsets	Medium	Backtracking	Backtracking	82.3%	37.5%	all
543	Diameter of Binary Tree	Easy	Trees	DFS / BFS	65.5%	37.5%	all
305	Number of Islands II	Hard	Graphs	BFS / DFS / Topological Sort	40.6%	37.5%	all
13	Roman to Integer	Easy	Strings	Hashing / Sliding Window	66.6%	37.5%	all
115	Distinct Subsequences	Hard	Core DSA	Implementation / Reasoning	51.9%	37.5%	all
125	Valid Palindrome	Easy	Strings	Hashing / Sliding Window	53.3%	37.5%	all
197	Rising Temperature	Easy	Core DSA	Implementation / Reasoning	51.3%	37.5%	all
1011	Capacity To Ship Packages Within D Days	Medium	Binary Search	Binary Search	73.9%	37.5%	all
72	Edit Distance	Medium	Dynamic Programming	State Transition	60.6%	37.5%	all
442	Find All Duplicates in an Array	Medium	Arrays	Sorting / Prefix / Scan	76.9%	37.5%	all
52	N-Queens II	Hard	Backtracking	Backtracking	78.7%	37.5%	all
1122	Relative Sort Array	Easy	Arrays	Sorting / Prefix / Scan	75.2%	37.5%	all
694	Number of Distinct Islands	Medium	Graphs	BFS / DFS / Topological Sort	62.8%	37.5%	all
438	Find All Anagrams in a String	Medium	Strings	Hashing / Sliding Window	53.8%	37.5%	all
395	Longest Substring with At Least K Repeating Characters	Medium	Strings; Trees	Hashing / Sliding Window; DFS / BFS; Sliding Window	46.3%	37.5%	all
141	Linked List Cycle	Easy	Linked List	Two Pointers	54.3%	37.5%	all
2402	Meeting Rooms III	Hard	Greedy	Greedy	51.5%	37.5%	all
332	Reconstruct Itinerary	Hard	Core DSA	Implementation / Reasoning	44.6%	37.5%	all
135	Candy	Hard	Core DSA	Implementation / Reasoning	48.5%	37.5%	all
692	Top K Frequent Words	Medium	Strings; Heap	Hashing / Sliding Window; Priority Queue	60.2%	37.5%	all
394	Decode String	Medium	Strings; Dynamic Programming; Stack / Queue	Hashing / Sliding Window; State Transition; Monotonic Stack / Simulation	62.6%	37.5%	all
1926	Nearest Exit from Entrance in Maze	Medium	Core DSA	Implementation / Reasoning	48.6%	37.5%	all
1642	Furthest Building You Can Reach	Medium	Core DSA	Implementation / Reasoning	50.9%	37.5%	all
26	Remove Duplicates from Sorted Array	Easy	Arrays	Sorting / Prefix / Scan; Two Pointers	62.8%	37.5%	all
815	Bus Routes	Hard	Core DSA	Implementation / Reasoning	47.3%	37.5%	all
287	Find the Duplicate Number	Medium	Arrays	Sorting / Prefix / Scan	64.3%	37.5%	all
279	Perfect Squares	Medium	Core DSA	Implementation / Reasoning	56.5%	37.5%	all

Walmart Labs DSA Interview Questions

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