LeetCode | Coupon Code Validator | C++ | Golang | Rust

In this video, we solve LeetCode 3606 – Coupon Code Validator, the daily LeetCode challenge, step by step. I start by breaking down the problem requirements using hand-drawn diagrams, showing: 👉 What makes a coupon code valid 👉 How to validate allowed characters efficiently 👉 How to check business line constraints 👉 Why inactive coupons must be filtered out 👉 How the final sorting logic works KEY CONCEPTS EXPLAINED ✔ ASCII character validation (letters, digits, underscore) ✔ Filtering based on predefined business categories ✔ Custom sorting logic and ordering rules ✔ Cross-language differences in C++, Golang, and Rust 🕛 Timestamps 00:00 – Problem statement and Logic 03:34 – C++ implementation 11:35 – Time and Space complexity 14:35 – Golang Explanation 16:25 – Rust Explanation This video is especially useful if you want to: 👉 Understand cross-language sorting pitfalls 👉 Build strong LeetCode daily consistency 👉 Write clean, interview-ready code If you enjoy clear explanations with diagrams and real reasoning, don’t forget to like 👍 and subscribe 🔔 for more LeetCode daily solutions.