gradient boosting

XGBoost and LightGBM win most tabular problems, and interviewers want more than 'it's boosting.' The signal is the fit-to-residuals mechanism plus the engineering (regularization, histograms, second-order) that makes it both fast and accurate.

XGBoost made boosting practical; LightGBM made it fast. The answer is histogram binning, gradient-based sampling, and leaf-wise growth, each with a real tradeoff. Here is what they do and where they bite.