DSA Problem List — Browse by Topic, Difficulty & Company | Interview Prep Buddy
Labs
Problem List
0 of 135 solved
Status#TitleDifficultyTopicsAsked InAcceptanceReward
1.Two Sum
Easy
ArraysHash Maps
+2
52%+10 XP
2.Contains Duplicate
Easy
ArraysHash Maps
68%+10 XP
3.Valid Parentheses
Easy
Stack
B+1
58%+15 XP
4.Maximum Subarray
Medium
ArraysDynamic Programming
+2
52%+20 XP
5.Reverse Linked List
Easy
Linked List
+1
72%+15 XP
7.Merge Two Sorted Lists
Easy
Linked ListRecursion
+1
65%+15 XP
27.Binary Search
Easy
Binary SearchArrays
62%+10 XP
35.Search in Rotated Sorted Array
Medium
Binary SearchArrays
+2
40%+25 XP
8.Maximum Depth of Binary Tree
Easy
TreesRecursion
75%+10 XP
9.Invert Binary Tree
Easy
TreesRecursion
77%+10 XP
10.Number of Islands
Medium
GraphsRecursion
+2
54%+25 XP
11.Clone Graph
Medium
GraphsHash Maps
+1
49%+25 XP
12.Min Stack
Medium
Stack
+2
53%+20 XP
13.Daily Temperatures
Medium
Stack
+1
47%+25 XP
14.Implement Queue using Stacks
Easy
QueueStack
68%+15 XP
16.Valid Palindrome
Easy
Two Pointers
+1
48%+10 XP
18.3Sum
Medium
Two PointersArrays
+2
35%+30 XP
19.Longest Substring Without Repeating Characters
Medium
Sliding WindowHash Maps
+3
35%+25 XP
20.Climbing Stairs
Easy
Dynamic Programming
+1
72%+10 XP
21.Coin Change
Medium
Dynamic Programming
+2
42%+30 XP
15.LRU Cache
Medium
Hash MapsLinked List
B
42%+30 XP
17.Valid Sudoku
Medium
ArraysHash Maps
57%+20 XP
22.Valid Anagram
Easy
ArraysHash Maps
B
63%+10 XP
23.Group Anagrams
Medium
ArraysHash Maps
+2
55%+20 XP
24.Product of Array Except Self
Medium
Arrays
+2
65%+20 XP
25.Top K Frequent Elements
Medium
ArraysHash Maps
Y!
62%+25 XP
26.Longest Consecutive Sequence
Medium
ArraysHash Maps
48%+25 XP
28.Two Sum II - Input Array Is Sorted
Medium
ArraysTwo Pointers
60%+15 XP
29.Container With Most Water
Medium
ArraysTwo Pointers
+2
56%+20 XP
31.Trapping Rain Water
Hard
ArraysTwo Pointers
+1
45%+30 XP
33.Best Time to Buy and Sell Stock
Easy
ArraysSliding Window
54%+15 XP
36.Longest Repeating Character Replacement
Medium
StringsSliding Window
51%+20 XP
37.Permutation in String
Medium
StringsSliding Window
46%+20 XP
39.Minimum Window Substring
Hard
StringsSliding Window
B
40%+30 XP
41.Sliding Window Maximum
Hard
ArraysSliding Window
B
43%+30 XP
42.Evaluate Reverse Polish Notation
Medium
StackArrays
in
47%+20 XP
43.Generate Parentheses
Medium
StackBacktracking
50%+20 XP
44.Car Fleet
Medium
StackSorting
44%+25 XP
45.Largest Rectangle in Histogram
Hard
StackArrays
42%+30 XP
30.Search a 2D Matrix
Medium
Binary SearchArrays
49%+20 XP
32.Koko Eating Bananas
Medium
Binary SearchArrays
50%+20 XP
34.Find Minimum in Rotated Sorted Array
Medium
Binary SearchArrays
49%+20 XP
38.Time Based Key-Value Store
Medium
Binary SearchHash Maps
S
53%+20 XP
40.Median of Two Sorted Arrays
Hard
Binary SearchArrays
40%+30 XP
46.Linked List Cycle
Easy
Linked ListTwo Pointers
B
48%+15 XP
47.Reorder List
Medium
Linked ListTwo Pointers
51%+20 XP
49.Remove Nth Node From End of List
Medium
Linked ListTwo Pointers
44%+20 XP
50.Copy List with Random Pointer
Medium
Linked ListHash Maps
B
53%+25 XP
51.Add Two Numbers
Medium
Linked ListRecursion
43%+20 XP
52.Merge k Sorted Lists
Hard
Linked ListHeap
47%+30 XP
53.Reverse Nodes in k-Group
Hard
Linked List
46%+30 XP
54.Diameter of Binary Tree
Easy
Trees
55%+15 XP
55.Balanced Binary Tree
Easy
Trees
51%+15 XP
56.Same Tree
Easy
Trees
B
58%+10 XP
57.Subtree of Another Tree
Easy
Trees
46%+15 XP
59.Lowest Common Ancestor of a Binary Search Tree
Medium
TreesBinary Search
61%+20 XP
60.Binary Tree Level Order Traversal
Medium
Trees
in
64%+20 XP
61.Binary Tree Right Side View
Medium
Trees
60%+20 XP
63.Count Good Nodes in Binary Tree
Medium
Trees
68%+20 XP
64.Validate Binary Search Tree
Medium
TreesBinary Search
B
52%+25 XP
65.Kth Smallest Element in a BST
Medium
TreesBinary Search
B
71%+20 XP
67.Construct Binary Tree from Preorder and Inorder Traversal
Medium
Trees
B
58%+25 XP
69.Binary Tree Maximum Path Sum
Hard
Trees
B
39%+30 XP
71.Serialize and Deserialize Binary Tree
Hard
Trees
57%+30 XP
152.Maximum Product Subarray
Medium
ArraysDynamic Programming
35%+15 XP
371.Sum of Two Integers
Medium
Bit Manipulation
51%+15 XP
191.Number of 1 Bits
Easy
Bit Manipulation
69%+10 XP
338.Counting Bits
Easy
Bit ManipulationDynamic Programming
77%+10 XP
268.Missing Number
Easy
ArraysBit Manipulation
66%+10 XP
190.Reverse Bits
Easy
Bit Manipulation
58%+10 XP
300.Longest Increasing Subsequence
Medium
Dynamic ProgrammingBinary Search
54%+15 XP
1143.Longest Common Subsequence
Medium
Dynamic Programming
58%+15 XP
139.Word Break
Medium
Dynamic ProgrammingHash Maps
46%+15 XP
48.Combination Sum
Medium
BacktrackingArrays
70%+15 XP
198.House Robber
Medium
Dynamic Programming
50%+15 XP
213.House Robber II
Medium
Dynamic Programming
41%+15 XP
91.Decode Ways
Medium
Dynamic Programming
34%+15 XP
62.Unique Paths
Medium
Dynamic Programming
63%+15 XP
68.Jump Game
Medium
GreedyDynamic Programming
38%+15 XP
207.Course Schedule
Medium
Graphs
46%+15 XP
417.Pacific Atlantic Water Flow
Medium
Graphs
55%+15 XP
269.Alien Dictionary
Hard
Graphs
36%+20 XP
261.Graph Valid Tree
Medium
Graphs
in
47%+15 XP
323.Number of Connected Components in an Undirected Graph
Medium
Graphs
62%+15 XP
72.Insert Interval
Medium
Arrays
40%+15 XP
70.Merge Intervals
Medium
ArraysSorting
47%+15 XP
435.Non-overlapping Intervals
Medium
GreedySorting
53%+15 XP
252.Meeting Rooms
Easy
SortingArrays
57%+10 XP
253.Meeting Rooms II
Medium
HeapSorting
50%+15 XP
73.Set Matrix Zeroes
Medium
Arrays
53%+15 XP
66.Spiral Matrix
Medium
Arrays
48%+15 XP
58.Rotate Image
Medium
Arrays
73%+15 XP
79.Word Search
Medium
BacktrackingArrays
41%+15 XP
6.Longest Palindromic Substring
Medium
Two PointersDynamic Programming
33%+15 XP
647.Palindromic Substrings
Medium
Two PointersDynamic Programming
69%+15 XP
271.Encode and Decode Strings
Medium
Arrays
45%+15 XP
208.Implement Trie (Prefix Tree)
Medium
Trie
62%+15 XP
211.Design Add and Search Words Data Structure
Medium
TrieBacktracking
44%+15 XP
212.Word Search II
Hard
TrieBacktracking
36%+20 XP
295.Find Median from Data Stream
Hard
Heap
51%+20 XP
78.Subsets
Medium
BacktrackingArrays
B
74%+20 XP
46.Permutations
Medium
BacktrackingArrays
+1
73%+20 XP
17.Letter Combinations of a Phone Number
Medium
BacktrackingHash Maps
+1
57%+20 XP
131.Palindrome Partitioning
Medium
BacktrackingDynamic Programming
B
63%+25 XP
300.Longest Increasing Subsequence
Medium
Dynamic ProgrammingBinary Search
+1
53%+25 XP
139.Word Break
Medium
Dynamic ProgrammingHash Maps
+1
44%+25 XP
91.Decode Ways
Medium
Dynamic Programming
B
30%+25 XP
1143.Longest Common Subsequence
Medium
Dynamic Programming
+1
56%+25 XP
416.Partition Equal Subset Sum
Medium
Dynamic ProgrammingArrays
47%+25 XP
994.Rotting Oranges
Medium
GraphsArrays
B
52%+20 XP
210.Course Schedule II
Medium
Graphs
+1
48%+25 XP
45.Jump Game II
Medium
GreedyArrays
+1
40%+25 XP
134.Gas Station
Medium
GreedyArrays
B
44%+25 XP
621.Task Scheduler
Medium
GreedyHeap
B
54%+25 XP
90.Subsets II
Medium
BacktrackingArrays
56%+20 XP
51.N-Queens
Hard
Backtracking
66%+30 XP
518.Coin Change II
Medium
Dynamic Programming
62%+25 XP
72.Edit Distance
Hard
Dynamic Programming
55%+30 XP
684.Redundant Connection
Medium
Graphs
63%+25 XP
743.Network Delay Time
Medium
Graphs
54%+25 XP
232.Implement Queue using Stacks
Easy
QueueStack
B
63%+15 XP
622.Design Circular Queue
Medium
QueueArrays
51%+20 XP
648.Replace Words
Medium
TrieHash Maps
63%+20 XP
136.Single Number
Easy
Bit ManipulationArrays
72%+15 XP
338.Counting Bits
Easy
Bit ManipulationDynamic Programming
77%+15 XP
1004.Max Consecutive Ones III
Medium
Sliding WindowArrays
63%+20 XP
215.Kth Largest Element in an Array
Medium
HeapSorting
67%+20 XP
125.Valid Palindrome
Easy
StringsTwo Pointers
+1
45%+15 XP
344.Reverse String
Easy
StringsTwo Pointers
77%+15 XP
14.Longest Common Prefix
Easy
Strings
41%+15 XP
392.Is Subsequence
Easy
StringsTwo Pointers
47%+15 XP
647.Palindromic Substrings
Medium
StringsDynamic Programming
68%+20 XP
443.String Compression
Medium
StringsTwo Pointers
53%+20 XP
438.Find All Anagrams in a String
Medium
StringsSliding Window
50%+20 XP
6.Zigzag Conversion
Medium
Strings
46%+20 XP