17. Roman to Integer – LeetCode 13 🔢 Smart Mapping + Greedy Logic | Top Interview 150

In this video from the LeetCode Top Interview 150 series, we crack Roman to Integer (LeetCode 13) using a clean greedy strategy with constant-time lookups.

🧠 Core Strategy Explained

1. Use a hash map to map Roman symbols to numeric values
2. Traverse the string left to right
3. Apply subtractive logic when a smaller numeral appears before a larger one (e.g., IV, IX, XL)
4. Skip ahead intelligently to avoid double counting

⚙️ Why This Approach Works

• Time Complexity: O(n)
• Space Complexity: O(1) (fixed-size map)
• Easy to reason about
• Interview-friendly and production-ready

This problem is a classic example of pattern recognition + greedy decision-making, frequently asked in product-based company interviews to test attention to detail and edge-case handling.

#LeetCode150 #LeetCode13 #RomanToInteger #GreedyAlgorithm #HashMap #DSA #CodingInterview #FAANG #Cpp #Algorithms #InterviewPreparation #CompetitiveProgramming #SoftwareEngineer #ProblemSolving #LeetCodeSolutions