Two-Sum Strategy: O(n) Solution with Hash Map

Day 9: Mastering the Two-Sum Strategy 🎯 💡 How I solved it: Instead of a slow O(n^2) nested loop to find pairs, I used a One-Pass Hash Map to achieve a lightning-fast O(n) solution. Target Calculation: For every number n, I calculated the diff (target - n) needed to complete the pair. Instant Lookup: I checked if this diff already existed in my prev_map. If it did, I immediately returned the indices. Dynamic Mapping: If the complement wasn't found, I stored the current number and its index {val: index} in the map to be used for future lookups. The Single Pass: This allowed me to find the answer in just one trip through the array. 🧠 Key Takeaway: Efficiency First: Trading a tiny bit of memory O(n) space for a massive gain in speed O(n) time is the hallmark of an optimized algorithm. Complement Logic: Learned that searching for a "pair" is really just searching for a "complement." Dictionary Power: This project reinforced how Python’s dictionary lookups are O(1) on average, making them the ultimate tool for reducing time complexity. One step closer to mastering Data Structures and Algorithms! 💻🔥 The logic is getting sharper every day! 📈🤝 #100DaysOfCode #DSA #Python #TwoSum #ProblemSolving #StriverA2ZSheet #CodingJourney

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