Microsoft OA High-Frequency Questions 2026

Recently completed the Microsoft 2026 SDE Online Assessment (New Grad + Intern). One-line summary: Stable structure, but increasing difficulty and time pressure. Platforms are mainly HackerRank or Codility , with a typical format: 2 questions 75–90 minutes (Codility sometimes 110 minutes) Questions are mostly Medium , occasionally Medium-Hard , with stronger emphasis on: Engineering thinking Edge case handling Code robustness 1. Stacks / Blocks Conversion Description: Given an array where each number represents a stack of blocks. Every 2 blocks can merge into 1 and carry to the next stack. Repeat until no more merges are possible. Return remaining single blocks. Example: [5,3,1] Key Idea: Simulate from left to right Carry-over like binary addition (base-2 behavior) Use long for large values (up to 1e9) Pitfalls: All 1s or all 0s Overflow issues Empty input 2. Circular Character Roll Description: Given a string s and an array roll , for each roll[i], increment the first roll[i] characte