company prep
Walmart
Problems frequently reported at Walmart, in course order. Solve the must-dos first.
3 easy29 medium2 hardFrequency counting ×4Two pointers (opposite ends) ×4Matrix traversal & in-place transforms ×2Counting / bucket sort ×2Sliding window (variable size) ×2Union-Find (DSU) ×2
02 · Arrays & Strings in Java
- #387First Unique Character in a StringEasymust-do
10 · Arrays & Strings
- #49Group AnagramsMediummust-do
- #31Next PermutationMediummust-do
11 · Matrices & Simulation
- #6Zigzag ConversionMedium
- #73Set Matrix ZeroesMediummust-do
12 · Two Pointers
- #153SumMediummust-do
- #11Container With Most WaterMediummust-do
- #42Trapping Rain WaterHardmust-do
- #75Sort ColorsMediummust-do
13 · Sliding Window
- #3Longest Substring Without Repeating CharactersMediummust-do
- #567Permutation in StringMediummust-do
14 · Hashing & Prefix Sums
- #128Longest Consecutive SequenceMediummust-do
15 · Linked Lists
- #876Middle of the Linked ListEasy
- #146LRU CacheMediummust-do
16 · Stacks & Monotonic Stack
- #20Valid ParenthesesEasymust-do
17 · Queues & Deques
- #362Design Hit CounterMedium
18 · Binary Search
- #33Search in Rotated Sorted ArrayMediummust-do
20 · String Parsing & Expression Evaluation
- #12Integer to RomanMedium
22 · Tree Recursion
24 · Heaps & Priority Queues
- #215Kth Largest Element in an ArrayMediummust-do
- #347Top K Frequent ElementsMediummust-do
- #621Task SchedulerMedium
- #295Find Median from Data StreamHardmust-do
26 · Graphs: BFS & DFS
- #200Number of IslandsMediummust-do
- #994Rotting OrangesMediummust-do
31 · Backtracking
- #39Combination SumMediummust-do
- #22Generate ParenthesesMediummust-do
33 · Intervals
- #56Merge IntervalsMediummust-do
35 · Dynamic Programming
- #198House RobberMediummust-do
- #139Word BreakMediummust-do
- #322Coin ChangeMediummust-do
- #300Longest Increasing SubsequenceMediummust-do
- #5Longest Palindromic SubstringMediummust-do
36 · DP Patterns
- #647Palindromic SubstringsMediummust-do