All Flashcards
What does this code do?
java
public static boolean isSorted(ArrayList<Integer> array) {
for (int i = 0; i < array.size() - 1; i++) {
if (array.get(i + 1) < array.get(i)) {
return false;
}
}
return true;
}
Checks if an ArrayList of Integers is sorted in ascending order.
What is the purpose of the outer loop in the selectionSort method?
To traverse to the second to last item in the ArrayList.
What is the purpose of the inner loop in the selectionSort method?
To find the smallest remaining item in the unsorted portion of the ArrayList.
What is the purpose of the outer loop in the insertionSort method?
To iterate through the ArrayList, considering each element for insertion into the sorted portion.
What is the purpose of the inner loop in the insertionSort method?
To shift elements to the right to create space for inserting the current element in its correct position.
What is the error in the following code?
java
public static ArrayList<Integer> selectionSort(ArrayList<Integer> array) {
for (int i = 0; i < array.size(); i++) { // Error is here
int smallestIndex = i;
int smallestElement = array.get(i);
for (int j = i + 1; j < array.size(); j++) {
if (array.get(j) < smallestElement) {
smallestIndex = j;
smallestElement = array.get(j);
}
}
if (smallestIndex > i) {
int originalItem = array.get(i);
array.set(i, smallestElement);
array.set(smallestIndex, originalItem);
}
}
return array;
}
The outer loop should iterate up to array.size() - 1 to avoid an IndexOutOfBoundsException.
What is the error in the following code?
java
public static ArrayList<Integer> insertionSort(ArrayList<Integer> array) {
for (int i = 1; i < array.size(); i++) {
int currentElement = array.get(i);
int currentIndex = i;
for (int j = i; j > 0; j++) {
if (currentElement < array.get(j - 1)) { // shifting the item left until properly placed by swapping consecutive items
int itemToRight = array.get(j - 1);
array.set(j - 1, currentElement);
array.set(j, itemToRight);
}
}
}
return array;
}
There is no error in the code.
Predict the output:
java
ArrayList<Integer> list = new ArrayList<>(Arrays.asList(5, 2, 8, 1, 9));
selectionSort(list);
System.out.println(list);
[1, 2, 5, 8, 9]
Predict the output:
java
ArrayList<Integer> list = new ArrayList<>(Arrays.asList(5, 2, 8, 1, 9));
insertionSort(list);
System.out.println(list);
[1, 2, 5, 8, 9]
Complete the code:
java
public static boolean isSorted(ArrayList<Integer> array) {
for (int i = 0; i < array.size() - 1; i++) {
if (array.get(i + 1) < array.get(i)) {
// Complete this line
}
}
return true;
}
return false;
What is Selection Sort?
A sorting algorithm that divides the list into sorted and unsorted subarrays, repeatedly finding the minimum element from the unsorted subarray and placing it at the beginning.
What is Insertion Sort?
A sorting algorithm that builds the final sorted array one item at a time by repeatedly inserting elements from the unsorted portion into the correct position in the sorted portion.
What is an ArrayList?
A resizable array implementation of the List interface.
What is a sorted array?
An array where elements are arranged in a specific order (ascending or descending).
What is a subarray?
A contiguous part of an array.
What is ascending order?
Arrangement from smallest to largest.
What is descending order?
Arrangement from largest to smallest.
What is swapping?
Exchanging the positions of two elements in an array.
What is an algorithm?
A step-by-step procedure for solving a problem.
What is run-time comparison?
Evaluating the efficiency of algorithms by counting statement executions.
What are the general steps of Selection Sort?
- Find the smallest element in the unsorted portion. 2. Swap it with the first element of the unsorted portion. 3. Repeat for the remaining unsorted portion.
What are the general steps of Insertion Sort?
- Assume the first element is sorted. 2. Take the next element and insert it into the correct position in the sorted portion. 3. Repeat for all remaining elements.
What are the steps to check if an ArrayList is sorted?
- Iterate through the list. 2. Compare each element with the next. 3. If any element is greater than the next, the list is not sorted.
Steps of Selection Sort (detailed)
- Find the minimum element in the unsorted array. 2. Swap the found minimum element with the first element of the unsorted array. 3. Move to the next element in the unsorted array. 4. Repeat until the array is sorted.
Steps of Insertion Sort (detailed)
- Iterate from the second element to the end of the array. 2. For each element, compare it with the elements before it. 3. Shift the elements greater than the current element to one position ahead of their current position. 4. Insert the current element in the correct position.
Steps to determine if an ArrayList is sorted (detailed)
- Start from the first element of the ArrayList. 2. Compare each element with the next element in the ArrayList. 3. If any element is greater than the next element, return false. 4. If the end of the ArrayList is reached, return true.
What is the first step in Selection Sort?
Find the smallest element in the unsorted portion.
What is the first step in Insertion Sort?
Assume the first element is sorted.
What is the first step to check if an ArrayList is sorted?
Iterate through the list.
What is the last step in Selection Sort?
Repeat for the remaining unsorted portion.