Citi计算机科学面经_Citi计算机科学面试真题及高频题

1.Leetcode Threesum Problem

2.Purpose and use cases of Unsafe

3.Differences between TreeMap, HashMap, and ConcurrentHashMap

1. Leetcode Threesum Problem

Solve the Leetcode Threesum problem. The task is to find all unique triplets in the array which gives the sum of zero.

2. Purpose and use cases of Unsafe

What is Unsafe used for in Java, and when would you use it?

3. Differences between TreeMap, HashMap, and ConcurrentHashMap

Explain the differences between TreeMap, HashMap, and ConcurrentHashMap in Java.