25Validate balanced parentheses/brackets, and explain the stack pattern.▼easy★ EssentialGoogleMetaAmazon2 replies◆ premiumA warm-up that screens for the stack instinct. The signal is recognizing last-opened-first-closed maps to a stack, and handling the edge cases (leftover opens, early close). Here is the pattern.Open full answer →
29Two Sum and the hash-map complement pattern.▼easy★ EssentialGoogleMetaAmazon2 replies◆ premiumThe canonical warm-up that screens for the hash-map instinct: trade space for time to turn O(n squared) into O(n). The signal is the one-pass complement lookup. Here is the pattern.Open full answer →
35Reverse a linked list (iterative and recursive), and the pointer-manipulation pattern.▼easy★ EssentialGoogleMetaAmazon1 replies◆ premiumReversing a linked list is the canonical pointer-handling screen. The signal is the three-pointer walk done without ever losing the rest of the list, plus knowing why the iterative version beats recursion in production. Here is the answer.Open full answer →
123Implement learning-rate schedulers from scratch: step decay, exponential decay, and cosine annealing.▼easyGoogleMetaNVIDIA1 replies◆ premiumA from-scratch test of how learning-rate schedules are actually computed. The signal is correct closed-form formulas, knowing when each schedule shines, and why decaying the rate helps convergence. Here is the implementation of the common ones.Open full answer →
47How do you evaluate a regression model (MAE, RMSE, R², MAPE)?▼easyAmazonGoogleMicrosoft1 replies◆ premiumRegression needs different metrics than classification, and each tells a different story. The signal is knowing what RMSE vs MAE vs R² vs MAPE actually measure and their failure modes around outliers, scale, and zeros.Open full answer →
22Why this company, and why this role? (And where do you see yourself going?)▼easy★ EssentialAmazonGoogleMeta1 replies◆ premiumA soft-sounding question that quietly screens out low-effort candidates and tests real fit. The signal is specific, researched reasons tied to your trajectory, not flattery. Here is the structure that lands.Open full answer →
28What is your biggest weakness?▼easyAmazonGoogleMeta2 replies◆ premiumThe classic question that screens for self-awareness and honesty, not for a perfect non-answer. The signal is a real weakness plus what you're actively doing about it. Here is how to answer it well.Open full answer →