1. ArrayList Exercises

Exercise 1: Remove Duplicates

Write a method that removes duplicate elements from an ArrayList while preserving the first occurrence order.

Method signature: public static ArrayList<Integer> removeDuplicates(ArrayList<Integer> list)

Example:

• Input: [3, 1, 2, 1, 4, 3, 5]
• Output: [3, 1, 2, 4, 5]

Exercise 2: Merge Two Sorted Lists

Merge two sorted ArrayLists into one sorted ArrayList.

Method signature: public static ArrayList<Integer> mergeSorted(ArrayList<Integer> list1, ArrayList<Integer> list2)

Example:

• Input: list1 = [1, 3, 5, 7], list2 = [2, 4, 6, 8]
• Output: [1, 2, 3, 4, 5, 6, 7, 8]

Exercise 3: ArrayList Partition

Write a method that partitions an ArrayList into two lists based on a predicate (even/odd numbers).

Method signature: public static ArrayList<ArrayList<Integer>> partition(ArrayList<Integer> list)

Example:

• Input: [1, 2, 3, 4, 5, 6]
• Output: [[2, 4, 6], [1, 3, 5]]

2. HashMap Exercises