All Flashcards
What are the differences between ArrayLists and arrays?
ArrayLists: Dynamic size, use methods | Arrays: Fixed size, use bracket notation
What are the differences between selection sort and insertion sort?
Selection Sort: Finds minimum and swaps | Insertion Sort: Inserts elements into correct position
What are the differences between using a for loop and a for-each loop to traverse an ArrayList?
For loop: Uses index, can modify | For-each loop: No index, cannot modify
What are the differences between add(E obj) and add(int index, E obj) in ArrayLists?
add(E obj): Appends to the end | add(int index, E obj): Inserts at a specific index
What are the differences between get(int index) and set(int index, E obj) in ArrayLists?
get(int index): Retrieves element at index | set(int index, E obj): Updates element at index
What are the differences between using primitive types and wrapper classes in ArrayLists?
Primitive types: Cannot be stored directly | Wrapper classes: Can be stored in ArrayLists
What are the differences between searching and sorting?
Searching: Locates a specific element | Sorting: Arranges all elements in order
What are the differences between arrays and ArrayLists in terms of memory usage?
Arrays: Allocate fixed memory | ArrayLists: Dynamically allocate memory, potentially more overhead
What are the differences between the best-case time complexity of selection sort and insertion sort?
Selection Sort: O(n^2) | Insertion Sort: O(n)
What are the differences between the worst-case time complexity of selection sort and insertion sort?
Selection Sort: O(n^2) | Insertion Sort: O(n^2)
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
list.add("apple");
list.add("banana");
System.out.println(list.size());
2
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(10);
list.add(20);
list.set(0, 15);
System.out.println(list.get(0));
15
Identify the error in the following code:
java
ArrayList<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
System.out.println(list.get(2));
IndexOutOfBoundsException: The index 2 is out of bounds for the list of size 2.
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
list.add("A");
list.add("B");
list.remove(0);
System.out.println(list.size());
1
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(5);
list.add(10);
list.add(5);
int index = list.indexOf(5);
System.out.println(index);
0
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
System.out.println(list.size());
0
Identify the error in the following code:
java
ArrayList<int> list = new ArrayList<>();
ArrayLists cannot store primitive types directly. Use the Integer wrapper class instead: ArrayList
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(1);
list.add(2);
list.add(3);
list.clear();
System.out.println(list.size());
0
What does the following code output?
java
ArrayList<String> list = new ArrayList<>();
list.add("apple");
list.add("banana");
System.out.println(list.get(1));
banana
What does the following code output?
java
ArrayList<Integer> list = new ArrayList<>();
list.add(5);
list.add(10);
list.remove(Integer.valueOf(5));
System.out.println(list.size());
1
What is an ArrayList?
A dynamic data structure that stores an ordered collection of items.
What does 'mutable' mean in the context of ArrayLists?
Elements can be changed after the ArrayList is created.
What is a wrapper class?
A class that encapsulates a primitive data type, turning it into an object.
What is linear search?
A method for finding a target element in a list by checking each element sequentially.
Define selection sort.
A sorting algorithm that repeatedly finds the minimum element and moves it to the sorted portion of the list.
Define insertion sort.
A sorting algorithm that inserts each element into its correct position in the already sorted portion of the list.
What is encryption?
The process of converting plain text into a code to protect data from unauthorized access.
What is traversing an ArrayList?
Accessing and processing each element in the ArrayList, usually within a loop.
What is the Java Collections Framework?
A set of interfaces and classes that provide implementations for common data structures.
Define personal data.
Any information that relates to an identifiable individual.