HCLTech

Global IT services and consulting company.

4 Rounds ~21 Days Medium
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The Interview Loop

Recruiter Screen (30 min)

Standard fit check, behavioral questions, and resume overview.

Technical Loop (3-4 Rounds)

Deep dive into domain knowledge, coding, and system design.

Interview Question Bank

Machine Learning Engineer • Technical • medium

How do you handle a highly imbalanced dataset in a binary classification problem, such as a fraud detection model for a banking client?

#Data Imbalance #Classification #SMOTE
Practice
Machine Learning Engineer • Technical • medium

Explain the difference between ROC-AUC and PR-AUC. In what specific business scenarios would you prefer PR-AUC?

#Evaluation Metrics #Statistics
Practice
Machine Learning Engineer • Technical • medium

Compare Random Forest and XGBoost. How do they handle bias and variance differently?

#Ensemble Methods #Trees #Bias-Variance Tradeoff
Practice
Machine Learning Engineer • Technical • medium

How do you encode categorical variables with extremely high cardinality (e.g., zip codes or product IDs) without blowing up the feature space?

#Feature Engineering #Data Preprocessing
Practice
Machine Learning Engineer • Technical • easy

Explain how the K-Means algorithm works under the hood and how you determine the optimal number of clusters.

#Unsupervised Learning #Clustering
Practice
Machine Learning Engineer • Technical • medium

Explain the kernel trick in Support Vector Machines (SVM). What are some common kernels used?

#SVM #Math
Practice
Machine Learning Engineer • Technical • medium

What are the core assumptions of Linear Regression? How do you check if they are violated in a real-world dataset?

#Statistics #Regression
Practice
Machine Learning Engineer • Technical • hard

How do you test for stationarity in a time series dataset, and what steps do you take if the data is non-stationary?

#Time Series #Statistics
Practice
Machine Learning Engineer • Technical • medium

Explain Principal Component Analysis (PCA). How does it differ from t-SNE in terms of use cases?

#Dimensionality Reduction #Math
Practice
Machine Learning Engineer • Technical • medium

How do you explain the predictions of a complex ensemble model (like LightGBM) to a non-technical business stakeholder?

#Model Explainability #SHAP #LIME
Practice

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The "Standard" Interviewer

Senior Engineer

Focuses on core competencies, system constraints, and clear communication.

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Unwritten Rules

Think Out Loud

Always explain your thought process before writing code or drawing architecture.

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