Goldman Sachs Associate Interview Questions and Answers

Immutable classes are classes whose instances cannot be modified after creation.

• Immutable classes have all fields marked as final and private.

• They do not have any setter methods to modify the state of the object.

• Any modification to an immutable object results in a new object being created.

• Example of an immutable class: public class Person { private final String name; private final int age; public Person(String name, int age) { this.name = name; this.age = age; } public String...read more

To improve model performance beyond hyperopt, consider ensemble methods, feature engineering, and data augmentation.

• Implement ensemble methods like bagging, boosting, or stacking to combine multiple models.

• Perform feature engineering to create new informative features or transform existing ones.

• Apply data augmentation techniques to increase the size and diversity of the training data.

• Consider using advanced algorithms like XGBoost, Random Forest, or Neural Networks.

• Regularize...read more

To tune model performance, adjust hyperparameters, preprocess data, increase training data, and use ensemble methods.

• Adjust hyperparameters such as learning rate, regularization, and batch size.

• Preprocess data by scaling, normalizing, or handling missing values.

• Increase training data to reduce overfitting and improve generalization.

• Use ensemble methods like bagging or boosting to combine multiple models.

• Perform cross-validation to evaluate model performance and select the bes...read more

Handling class imbalance involves techniques such as resampling, adjusting class weights, and using ensemble methods.

• Resampling techniques like oversampling the minority class or undersampling the majority class can help balance the classes.

• Adjusting class weights during model training can give more importance to the minority class.

• Using ensemble methods like bagging or boosting can improve the performance on imbalanced datasets.

• Applying anomaly detection or one-class classif...read more

Use a hashmap to store the frequency of each character and then iterate through the string to find the first non-repeating character.

• Create a hashmap to store the frequency of each character in the string.

• Iterate through the string and update the frequency in the hashmap.

• Iterate through the string again and return the first character with frequency 1.

XGBoost is an optimized version of Gradient Boosting Machine (GBM) with additional features and improvements.

• XGBoost is a scalable and efficient implementation of gradient boosting algorithm.

• XGBoost uses a more regularized model formalization to control overfitting.

• XGBoost supports parallel processing and can handle large datasets.

• XGBoost provides built-in regularization techniques like L1 and L2 regularization.

• XGBoost has a variety of objective functions and evaluation metri...read more

Design a distributed rate limiter for managing incoming requests.

• Use a distributed key-value store like Redis to store request counts and timestamps.

• Implement a token bucket algorithm to control the rate of incoming requests.

• Use a distributed messaging system like Kafka for communication between rate limiter instances.

• Consider using consistent hashing to evenly distribute requests among rate limiter instances.