LeetCode Was Hard Until I Learned THESE 8 Patterns (With Templates!)

Almost all LeetCode problems can be solved with the same 8 patterns, and in this video, we'll explain the patterns and provide CODE TEMPLATES you can copy and use to solve any question!

Chapters
0:00 - Intro
0:49 - Two Pointers
2:29 - Sliding Window
4:20 - Binary Search
7:34 - BFS
10:08 - DFS
13:08 - Backtracking
16:58 - Priority Queue (Heap)
19:01 - Dynamic Programming

#leetcode #codinginterview #algorithms

[yashshukla]

- **Introduction:**
- 8 important patterns for coding interviews split into two categories:
- **Linear structures:** arrays, linked lists, strings.
- **Nonlinear structures:** trees, graphs.
- Focus on pre-built code templates for these patterns.

- **Linear Data Structure Patterns:**
1. **Two Pointers:**
- Reduces time complexity to linear time \(O(n)\).
- Two methods:
- Same direction: used for scanning data in a single pass (e.g., fast and slow pointers to detect cycles or find middle elements).
- Opposite directions: used for finding pairs (e.g., sum of two numbers in a sorted array).
2. **Sliding Window:**
- Refines two pointers to manage a window of elements dynamically.
- Expands or contracts the window to meet specific conditions (e.g., longest substring without repeating characters).
- Often combined with hashmaps.
3. **Binary Search:**
- Efficiently finds target in logarithmic time \(O(\log n)\).
- Extends to lists with monotonic conditions, not just sorted numbers.
- Example: finding the minimum in a rotated sorted array.

- **Nonlinear Data Structure Patterns:**
4. **Breadth-First Search (BFS):**
- Explores nodes level by level.
- Uses a queue to keep track of visited nodes (ideal for level order traversal).
5. **Depth-First Search (DFS):**
- Dives deep into one path before exploring others.
- Often uses recursion and is memory efficient for exploring all paths.
- Example: counting islands in a grid.
6. **Backtracking:**
- Extension of DFS, explores all possible solutions.
- Builds the solution dynamically by making decisions and backtracking on invalid paths.
- Example: letter combinations of a phone number.

- **Heaps (Priority Queue):**
7. **Heaps:**
- Used for questions related to top K, K smallest/largest.
- **Min Heap:** smallest value at the root.
- **Max Heap:** largest value at the root.
- Max Heap is used to find K smallest values, and vice versa for K largest.

- **Dynamic Programming (DP):**
8. **Dynamic Programming:**
- Optimizes solutions by breaking problems into overlapping subproblems.
- Two approaches:
- **Top-down:** recursive with memoization to store results.
- **Bottom-up:** solves smaller subproblems iteratively using a table.
- Too complex for this video but covered in-depth on their website.

[xEveNxThExOdds]

one of the best videos on the topic i’ve seen, thank you

[ytrg]

Excellent! Thank you so much for this video. All of the data structures can be overwhelming to remember, you breaking them down into categories, with their use cases, and providing templates was so useful.

[stanrobertson]

Thanks for the update, Anna! It is great that you are sharing your experience so that others can have hope.

[sahiljain]

thanks a lot man. never thought of solving leetcode as templates .this is really helpful.

[nathsai]

Absolutely loved this video!
Thanks a lot!

[Website_TV_]

Struggling with LeetCode? Not anymore! 🚀 These 8 patterns and templates are game-changers for tackling even the toughest problems! 🤯 I wish I learned these earlier – it would have saved me HOURS of frustration. If you're aiming to ace your coding interviews, this video is a MUST-WATCH! 🧑‍💻✨

⚡ Pro tip: Stick around till the end for an epic bonus! 💡
time stamp:
0:00 - Intro
0:49 - Two Pointers
2:29 - Sliding Window
4:20 - Binary Search
7:34 - BFS
10:08 - DFS
13:08 - Backtracking
16:58 - Priority Queue (Heap)
19:01 - Dynamic Programming

[brandonbraner]

well this video worked, just signed up for the black Friday special :)

[pravinprince]

Thank you so much sir for the wonderful video

[robbyoconnor]

16:38 The background music is a huge mistake... it's very relaxing

[ricardosilva]

Regarding Binary Search for the "Find Minimum in Rotated Sorted Array" problem, I'm a bit unsure if the boolean array approach works. For example, if we have the rotated array of [50, 60, 70, 80, 90, 10, 20, 30, 40], wouldn't the approach return 20 instead of 10?

[IceGamerification]

where do i check this stuff out again?

[rohan]

Unable to buy your course from India. It say "Merchant is non-compliant with RBI guidelines for recurring payments and e-mandate".

And yes I have international payments on on my card

[kayalvizhi]

Is any one tell me..
Learning dsa is useful for careee or not?

[AmitNayekamit]

In `DFS` function 16:07 path.pop() never execute.

[roushanv]

Absolutely, i just don't remember how many times i have been asked binary search like finding indices of the numbers repeated in a sorted array 😂

[GauravSrivastava-cq]

dont know why but feel little bit of confident by seeing some medium level could be solved by patterns

[nishantsharma]

but there are no jobs what would i do after learning all this?

[mobiledevelopmentmastery]

Could you share some discount for your subscription?

[TheGIQ]

For the TF question (binary search) you forgot to stipulate that the input only has false, then true (can’t do TFTF)

Also, the vocal AI had a hiccup at the 9m mark lmao