Prerequisite: ArrayList in Java Given an ArrayList, the task is to get the first and last element of the ArrayList in Java, Examples:
Input: ArrayList = [1, 2, 3, 4] Output: First = 1, Last = 4 Input: ArrayList = [12, 23, 34, 45, 57, 67, 89] Output: First = 12, Last = 89
Approach:
- Get the ArrayList with elements.
- Get the first element of ArrayList with use of get(index) method by passing index = 0.
- Get the last element of ArrayList with use of get(index) method by passing index = size – 1.
Below is the implementation of the above approach:Â
Java
// Java code to find first and last element// of ArrayListÂ
import java.util.ArrayList;Â
public class GFG {Â
    // main method    public static void main(String[] args)    {Â
        // creating an Empty Integer ArrayList        ArrayList<Integer> list = new ArrayList<Integer>(5);Â
        // using add() to initialize values        list.add(1);        list.add(2);        list.add(3);        list.add(4);Â
        // printing initial value ArrayList        System.out.print("ArrayList: " + list);Â
        // find first element        int first = list.get(0);Â
        // find last element        int last = list.get(list.size() - 1);Â
        // print first and last element of ArrayList        System.out.println("\nFirst : " + first                           + ", Last : " + last);    }} |
Output:
ArrayList: [1, 2, 3, 4] First : 1, Last : 4
Time Complexity: O(1)
Auxiliary Space: O(1)
