Скачать или смотреть Day 1 – Arrays & Strings | Common Patterns + Bonus | Leetcode Interview Crash Course (DSA)

This is Day 1 of my Leetcode Interview Crash Course — a fast-paced, 7-day prep series covering all the core Data Science & DSA patterns.

In this video, I cover common array and string tricks that frequently appear in coding interviews, building on what we learned in the previous two videos on Two Pointers and Sliding Window.

You’ll learn about:

Efficient string building (O(n) vs O(n²))

Subarrays vs Subsequences vs Subsets

When to use Sliding Window, Two Pointers, or Prefix Sum

A live coding demo: Reverse Words in a String

A final bonus: Minimum Size Subarray Sum using Sliding Window


00:00 — Intro & Recap of Course
00:45 — String Building & Immutability (O(n²) Trap)
03:10 — How to Build Strings Efficiently (Using Lists + Join)
05:20 — Understanding Subarrays, Subsequences & Subsets
07:40 — When to Use Sliding Window vs Two Pointers
09:10 — Quick Quiz & Recap of Array/String Patterns
10:00 — Bonus Problem 1: Reverse Words in a String (Leetcode 557)
15:40 — Bonus Problem 2: Minimum Size Subarray Sum (Leetcode 209)
19:30 — Wrap-Up & Preview: Next Topic — Hashing