Course 1 · Data Structures & Algorithms

DSA LeetCode Sheet in Java

352 LeetCode problems that go with the free DSA course on YouTube, listed in the same order as the videos.

Each problem has a short summary, hints you open one at a time, the approach, a commented Java solution, time/space complexity and one common mistake.

Start from problem 1 Watch the course
Your progress0 / 352
26
topics
112
easy
192
medium
48
hard

The DSA path

15 modules, 105 episodes, one direction. The orange stations are out now — the rest light up as new episodes go live.

  1. 0Foundations
  2. 1Arrays
  3. 2Strings
  4. 3Searching & Sorting
  5. 4Recursion & Backtracking
  6. 5Hashing
  7. 6Linked List
  8. 7Stack & Queue
  9. 8Trees
  10. 9Heaps
  11. 10Greedy
  12. 11Graphs
  13. 12Dynamic Programming
  14. 13Advanced DS
  15. 14Interview Prep

Episodes out now

Each one has the video, a written summary, the key moments and the full transcript. See all episodes →

Episode 1 · 17:35
DSA Roadmap 2026: Zero to Hired in 6 Months (Complete Guide)
Episode 2 · 12:30
Big O Notation Explained Simply | Time and Space Complexity in DSA
Episode 3 · 21:12
How to Calculate Time Complexity of an Algorithm | Loops & Recursion
Episode 4 · 16:50
Complete Java for DSA: Collections, Arrays, Strings & Traps
Episode 5 · 13:22
Basic Math for DSA: Primes, Sieve, GCD & Modulo (Java)
Episode 6 · 13:32
Bit Manipulation from Scratch: AND, OR, XOR, Shifts & Tricks (Java)
Episode 7 · 11:26
Array Data Structure in Java Explained Simply | DSA for Beginners
Episode 8 · 10:55
Prefix Sum Explained: Any Range Sum in 1 Step | Java DSA
Episode 9 · 9:59
Two Pointers in Java: 5 Must-Know Patterns | DSA

Topics

Pick up where the videos are. Each card fills up as you solve its problems.

01
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Time & Space Complexity

Warm-up problems where the point is to say the Big O of your own code before you submit it.

6 problems · 0 solved ▶ Video live · Eps 2–3
02
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Java Basics for DSA

Arrays, Strings, StringBuilder and Collections — the Java toolbox every later topic uses.

10 problems · 0 solved ▶ Video live · Ep 4
03
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Basic Math

Primes, GCD, modulo, digits and the Sieve of Eratosthenes.

13 problems · 0 solved ▶ Video live · Ep 5
04
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Bit Manipulation

AND, OR, XOR, shifts and the classic bit tricks.

12 problems · 0 solved ▶ Video live · Ep 6
05
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Arrays

Traversal, in-place updates, rotation and the top array interview questions.

14 problems · 0 solved ▶ Video live · Eps 7–15
06
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Prefix Sum

Precompute running totals so range questions become O(1).

12 problems · 0 solved ▶ Video live · Ep 8
07
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Two Pointers

Opposite ends, same direction, and merging — two indexes instead of nested loops.

13 problems · 0 solved ▶ Video live · Ep 9
08
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Sliding Window

Fixed and variable windows over arrays and strings.

14 problems · 0 solved Ep 10
09
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Kadane, Dutch Flag & Moore's Voting

Three famous one-pass array algorithms and their variations.

9 problems · 0 solved Eps 11–13
10
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2D Arrays & Matrix

Rotate, spiral, search and in-place tricks on grids.

10 problems · 0 solved Ep 14
11
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Strings

StringBuilder, palindromes, anagrams, frequency counting and top string questions.

15 problems · 0 solved Eps 16–20
12
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String Pattern Matching

KMP, Rabin-Karp and the Z-algorithm.

7 problems · 0 solved Eps 18–19
13
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Binary Search

Lower/upper bound, rotated arrays and binary search on the answer.

17 problems · 0 solved Eps 21–23
14
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Sorting

Merge sort, quick sort, counting/bucket sort and custom comparators.

11 problems · 0 solved Eps 24–28
15
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Recursion & Backtracking

Subsets, permutations, combinations, N-Queens, Sudoku and word search.

18 problems · 0 solved Eps 29–36
16
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Hashing

HashMap and HashSet patterns: counting, grouping and prefix-sum maps.

12 problems · 0 solved Eps 37–39
17
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Linked List

Reverse, fast & slow pointers, merge, and LRU cache.

19 problems · 0 solved Eps 40–45
18
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Stack & Queue

Parentheses, expression evaluation, monotonic stack and deque.

18 problems · 0 solved Eps 46–52
19
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Binary Trees

Traversals, BFS, height/diameter, views, LCA, construction and serialization.

20 problems · 0 solved Eps 53–60
20
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Binary Search Trees

Insert, delete, validate, kth smallest and BST iterators.

12 problems · 0 solved Eps 61–63
21
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Heaps & Priority Queue

Top K, k-way merge and the two-heap median pattern.

13 problems · 0 solved Eps 64–68
22
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Greedy

Intervals, jump game, gas station and exchange arguments.

14 problems · 0 solved Eps 69–73
23
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Graphs

BFS/DFS, islands, cycles, topo sort, bipartite, shortest paths, MST, DSU, SCC and bridges.

21 problems · 0 solved Eps 74–85
24
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Dynamic Programming

1D, grid, knapsack, subsequences, strings, stocks, partition, trees and bitmask DP.

28 problems · 0 solved Eps 86–96
25
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Trie

Prefix trees for words, autocomplete and XOR tricks.

8 problems · 0 solved Ep 97
26
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Segment Tree, Fenwick & Sparse Table

Range queries with point updates.

6 problems · 0 solved Eps 98–100