DSA Study Tracker: 248 Topics for Data Engineers

DSA solved0 of 248

Solved, Rev 1, Rev 2, Rev 3 and a confidence score (1–5) for each topic, as in the planner spreadsheet. A topic counts as complete once it is marked solved.

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DSA tracker
#	Topic	Category	Level
1	Majority Element	Arrays	Easy
2	Find Pivot Index	Arrays	Easy
3	Product of Array Except Self	Arrays	Medium
4	Subarray Sum Equals K	Arrays	Medium
5	Subarray Sums Divisible by K	Arrays	Medium
6	Contiguous Array	Arrays	Medium
7	Shortest Subarray with Sum at Least K	Arrays	Hard
8	Maximum Subarray	Arrays	Medium
9	Maximum Product Subarray	Arrays	Medium
10	Maximum Subarray Sum with One Deletion	Arrays	Medium
11	Maximum Absolute Sum of Any Subarray	Arrays	Medium
12	Maximum Sum Circular Subarray	Arrays	Medium
13	Rotate Image	Arrays	Medium
14	Spiral Matrix	Arrays	Medium
15	Set Matrix Zeroes	Arrays	Medium
16	Missing Number	Arrays	Easy
17	Find All Numbers Disappeared in an Array	Arrays	Easy
18	Set Mismatch	Arrays	Easy
19	Find All Duplicates in an Array	Arrays	Medium
20	First Missing Positive	Arrays	Hard
21	Contains Duplicate	Hashing	Easy
22	Valid Anagram	Hashing	Easy
23	Two Sum	Hashing	Easy
24	First Unique Character in a String	Hashing	Easy
25	Longest Palindrome	Hashing	Easy
26	Ransom Note	Hashing	Easy
27	Valid Sudoku	Hashing	Medium
28	Group Anagrams	Hashing	Medium
29	Longest Consecutive Sequence	Hashing	Medium
30	Longest Common Prefix	Strings	Easy
31	Reverse String	Strings	Easy
32	Encode and Decode Strings	Strings	Medium
33	String to Integer (atoi)	Strings	Medium
34	Number of 1 Bits	Bit Manipulation	Easy
35	Reverse Bits	Bit Manipulation	Easy
36	Single Number	Bit Manipulation	Easy
37	Counting Bits	Bit Manipulation	Easy
38	Complement of Base 10 Integer	Bit Manipulation	Easy
39	Sum of Two Integers	Bit Manipulation	Medium
40	Single Number III	Bit Manipulation	Medium
41	Valid Palindrome II	Two Pointers	Easy
42	Valid Palindrome	Two Pointers	Easy
43	Move Zeroes	Two Pointers	Easy
44	Remove Duplicates from Sorted Array	Two Pointers	Easy
45	Squares of a Sorted Array	Two Pointers	Easy
46	Segregate 0s and 1s	Two Pointers	Easy
47	Backspace String Compare	Two Pointers	Easy
48	Two Sum II Input Array Is Sorted	Two Pointers	Medium
49	3Sum	Two Pointers	Medium
50	Container With Most Water	Two Pointers	Medium
51	Sort Colors	Two Pointers	Medium
52	3Sum Closest	Two Pointers	Medium
53	Triplets with Smaller Sum	Two Pointers	Medium
54	Subarray Product Less Than K	Two Pointers	Medium
55	4Sum	Two Pointers	Medium
56	Shortest Unsorted Continuous Subarray	Two Pointers	Medium
57	Trapping Rain Water	Two Pointers	Hard
58	Implement Stack using Queues	Queue	Easy
59	Implement Queue using Stacks	Queue	Easy
60	Number of Recent Calls	Queue	Easy
61	Design Circular Queue	Queue	Medium
62	Best Time to Buy and Sell Stock	Sliding Window	Easy
63	Max Sum Subarray of Size K	Sliding Window	Easy
64	Longest Substring Without Repeating Characters	Sliding Window	Medium
65	Longest Repeating Character Replacement	Sliding Window	Medium
66	Permutation in String	Sliding Window	Medium
67	Minimum Size Subarray Sum	Sliding Window	Medium
68	Longest K unique characters substring	Sliding Window	Medium
69	Fruit Into Baskets	Sliding Window	Medium
70	Max Consecutive Ones III	Sliding Window	Medium
71	Find All Anagrams in a String	Sliding Window	Medium
72	Minimum Window Substring	Sliding Window	Hard
73	Sliding Window Maximum	Sliding Window	Hard
74	Substring with Concatenation of All Words	Sliding Window	Hard
75	Valid Parentheses	Stack	Easy
76	Remove All Adjacent Duplicates In String	Stack	Easy
77	Min Stack	Stack	Medium
78	Evaluate Reverse Polish Notation	Stack	Medium
79	Remove All Adjacent Duplicates in String II	Stack	Medium
80	Simplify Path	Stack	Medium
81	Next Greater Element I	Stack	Easy
82	Daily Temperatures	Stack	Medium
83	Car Fleet	Stack	Medium
84	Next Greater Element II	Stack	Medium
85	Remove Nodes From Linked List	Stack	Medium
86	Remove K Digits	Stack	Medium
87	132 Pattern	Stack	Medium
88	Largest Rectangle in Histogram	Stack	Hard
89	Binary Search	Binary Search	Easy
90	Ceil in Sorted Array	Binary Search	Easy
91	Time Based Key-Value Store	Binary Search	Medium
92	Find First and Last Position	Binary Search	Medium
93	Number of Occurrence	Binary Search	Medium
94	Median of Two Sorted Arrays	Binary Search	Hard
95	Find Rotation Count	Binary Search	Easy
96	Find Minimum in Rotated Sorted Array	Binary Search	Medium
97	Search in Rotated Sorted Array	Binary Search	Medium
98	Peak Index in a Mountain Array	Binary Search	Medium
99	Find Peak Element	Binary Search	Medium
100	Koko Eating Bananas	Binary Search	Medium
101	Minimum Number of Days to Make m Bouquets	Binary Search	Medium
102	Aggressive Cows	Binary Search	Medium
103	Maximum Candies Allocated to K Children	Binary Search	Medium
104	Capacity To Ship Packages Within D Days	Binary Search	Medium
105	Split Array Largest Sum	Binary Search	Hard
106	Search a 2D Matrix	Binary Search	Medium
107	Search a 2D Matrix II	Binary Search	Medium
108	Kth Smallest Element in a Sorted Matrix	Binary Search	Medium
109	Merge Two Sorted Lists	Linked List	Easy
110	Remove Nth Node From End of List	Linked List	Medium
111	Copy List with Random Pointer	Linked List	Medium
112	Add Two Numbers	Linked List	Medium
113	LRU Cache	Linked List	Medium
114	Linked List Cycle	Linked List	Easy
115	Happy Number	Linked List	Easy
116	Middle of the Linked List	Linked List	Easy
117	Palindrome Linked List	Linked List	Easy
118	Reorder List	Linked List	Medium
119	Find the Duplicate Number	Linked List	Medium
120	Linked List Cycle II	Linked List	Medium
121	Circular Array Loop	Linked List	Medium
122	Reverse Linked List	Linked List	Easy
123	Reverse Linked List II	Linked List	Medium
124	Swap Nodes in Pairs	Linked List	Medium
125	Rotate List	Linked List	Medium
126	Reverse Nodes in k-Group	Linked List	Hard
127	Invert Binary Tree	Trees	Easy
128	Maximum Depth of Binary Tree	Trees	Easy
129	Diameter of Binary Tree	Trees	Easy
130	Balanced Binary Tree	Trees	Easy
131	Same Tree	Trees	Easy
132	Subtree of Another Tree	Trees	Easy
133	Count Good Nodes in Binary Tree	Trees	Medium
134	Construct Tree from Preorder and Inorder	Trees	Medium
135	Lowest Common Ancestor of Binary Tree	Trees	Medium
136	Binary Tree Maximum Path Sum	Trees	Hard
137	Serialize and Deserialize Binary Tree	Trees	Hard
138	Binary Tree Level Order Traversal	Trees	Medium
139	Binary Tree Right Side View	Trees	Medium
140	Implement Trie (Prefix Tree)	Trees	Medium
141	Design Add and Search Words	Trees	Medium
142	Extra Characters in a String	Trees	Medium
143	Search Suggestions System	Trees	Medium
144	Word Search II	Trees	Hard
145	Convert Sorted Array to BST	BST	Easy
146	Validate Binary Search Tree	BST	Medium
147	Kth Smallest Element in a BST	BST	Medium
148	Lowest Common Ancestor of a BST	BST	Medium
149	Insert into a BST	BST	Medium
150	Delete Node in a BST	BST	Medium
151	Kth Largest Element in a Stream	Heap	Easy
152	Last Stone Weight	Heap	Easy
153	Top K Frequent Elements	Heap	Medium
154	K Closest Points to Origin	Heap	Medium
155	Kth Largest Element in an Array	Heap	Medium
156	Task Scheduler	Heap	Medium
157	Min Cost to Connect Ropes	Heap	Medium
158	Sort Characters By Frequency	Heap	Medium
159	Find K Closest Elements	Heap	Medium
160	Reorganize String	Heap	Medium
161	Maximum Frequency Stack	Heap	Hard
162	Maximum Sum Combination	Heap	Medium
163	Find Median from Data Stream	Heap	Hard
164	Sliding Window Median	Heap	Hard
165	IPO	Heap	Hard
166	Design Twitter	Heap	Medium
167	Merge k Sorted Lists	Heap	Hard
168	Smallest Range Covering Elements from K Lists	Heap	Hard
169	Jump Game	Greedy	Medium
170	Jump Game II	Greedy	Medium
171	Gas Station	Greedy	Medium
172	Hand of Straights	Greedy	Medium
173	Merge Triplets to Form Target	Greedy	Medium
174	Partition Labels	Greedy	Medium
175	Valid Parenthesis String	Greedy	Medium
176	Maximum Length of Pair Chain	Greedy	Medium
177	Minimum Add to Make Parentheses Valid	Greedy	Medium
178	Remove Duplicate Letters	Greedy	Medium
179	Meeting Rooms	Greedy	Easy
180	Merge Intervals	Greedy	Medium
181	Insert Interval	Greedy	Medium
182	Non-overlapping Intervals	Greedy	Medium
183	Interval List Intersections	Greedy	Medium
184	Meeting Rooms II	Greedy	Medium
185	My Calendar I	Greedy	Medium
186	Generate Parentheses	Backtracking	Medium
187	Subsets	Backtracking	Medium
188	Permutations	Backtracking	Medium
189	Subsets II	Backtracking	Medium
190	Letter Combinations of a Phone Number	Backtracking	Medium
191	Letter Case Permutation	Backtracking	Medium
192	Combination Sum	Backtracking	Medium
193	Combination Sum II	Backtracking	Medium
194	Word Search	Backtracking	Medium
195	Palindrome Partitioning	Backtracking	Medium
196	N-Queens	Backtracking	Hard
197	Sudoku Solver	Backtracking	Hard
198	Find if Path Exists in Graph	Graph	Easy
199	Clone Graph	Graph	Medium
200	Number of Provinces	Graph	Medium
201	Word Ladder	Graph	Hard
202	Reconstruct Itinerary	Graph	Hard
203	Flood Fill	Graph	Easy
204	Island Perimeter	Graph	Easy
205	Number of Islands	Graph	Medium
206	Max Area of Island	Graph	Medium
207	Pacific Atlantic Water Flow	Graph	Medium
208	Surrounded Regions	Graph	Medium
209	Rotting Oranges	Graph	Medium
210	Number of Closed Islands	Graph	Medium
211	Course Schedule	Graph	Medium
212	Course Schedule II	Graph	Medium
213	Topological Sort	Graph	Medium
214	Minimum Height Trees	Graph	Medium
215	Alien Dictionary	Graph	Hard
216	Graph Valid Tree	Graph	Medium
217	Number of Connected Components	Graph	Medium
218	Redundant Connection	Graph	Medium
219	Is Graph Bipartite?	Graph	Medium
220	Path With Minimum Effort	Graph	Medium
221	Network Delay Time	Graph	Medium
222	Cheapest Flights Within K Stops	Graph	Medium
223	Min Cost to Connect All Points	Graph	Medium
224	Swim in Rising Water	Graph	Hard
225	Climbing Stairs	Dynamic Programming	Easy
226	Min Cost Climbing Stairs	Dynamic Programming	Easy
227	House Robber	Dynamic Programming	Medium
228	House Robber II	Dynamic Programming	Medium
229	Decode Ways	Dynamic Programming	Medium
230	Coin Change	Dynamic Programming	Medium
231	Word Break	Dynamic Programming	Medium
232	Longest Increasing Subsequence	Dynamic Programming	Medium
233	Best Time to Buy/Sell with Cooldown	Dynamic Programming	Medium
234	Partition Equal Subset Sum	Dynamic Programming	Medium
235	Coin Change II	Dynamic Programming	Medium
236	Target Sum	Dynamic Programming	Medium
237	0 - 1 Knapsack Problem	Dynamic Programming	Medium
238	Subset Sum Problem	Dynamic Programming	Medium
239	Count Subsets with Sum	Dynamic Programming	Medium
240	Partition Into 2 Subsets with Min Sum Diff	Dynamic Programming	Hard
241	Longest Palindromic Substring	Dynamic Programming	Medium
242	Palindromic Substrings	Dynamic Programming	Medium
243	Unique Paths	Dynamic Programming	Medium
244	Longest Common Subsequence	Dynamic Programming	Medium
245	Interleaving String	Dynamic Programming	Medium
246	Edit Distance	Dynamic Programming	Medium
247	Burst Balloons	Dynamic Programming	Hard
248	Regular Expression Matching	Dynamic Programming	Hard

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