Construct String with Distinct Characters in Windows

✅ Day 592: Accepted on Codeforces! Problem B — Construct the String | Round 634 (Div. 3) One line of code. That's all it took. 🤯 Sometimes competitive programming rewards you for thinking smart, not hard! 🔗Problem Link: https://lnkd.in/g9rzf8JQ 🧩 The Problem: Construct a string of length n such that every consecutive window of size a contains exactly b distinct characters. Use the smallest possible letters of the alphabet. 💡 The Insight — Pure Pattern Recognition: Ask yourself: what's the simplest string that guarantees every window of size a has exactly b distinct characters? 🔑 Just repeat the first b letters of the alphabet cyclically, across all n characters! Why does it work? Any window of size a ≥ b will always contain a full cycle of those b letters ✅ No extra letters are introduced → exactly b distinct chars, never more, never less ✅ Repeating cyclically ensures every window satisfies the constraint ✅ So the formula becomes: For position i → character = chr(ord('a') + i % b) Example: n=7, a=5, b=3 → abcabca ✨ n=6, a=1, b=1 → aaaaaa ✨ n=5, a=2, b=2 → ababa ✨ 📌 Key Takeaway: Before writing complex logic, always ask — "Does a simple repeating pattern satisfy all constraints?" In construction problems, the answer is often YES! 🎯 The elegance of competitive programming lies in finding the minimum structure that satisfies maximum constraints. 🧠 📧 sanjaykasaudhan09@gmail.com 📱 +91-9170580657 📋 Connect with me: https://lnkd.in/g_dRWtri #Codeforces #CompetitiveProgramming #Python #StringConstruction #OneLiner #DSA #ProblemSolving #Accepted #CodingJourney #Programming

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