All Flashcards
What is Binary Search?
A search algorithm that finds the position of a target value within a sorted array by repeatedly dividing the search interval in half.
What is Merge Sort?
A divide-and-conquer sorting algorithm that divides the input array into smaller sub-arrays, recursively sorts them, and then merges the sorted sub-arrays.
What is Recursion?
A programming technique where a function calls itself in order to solve a problem.
What is a Base Case?
The condition that stops a recursive function from calling itself infinitely.
What is Linear Search?
A searching algorithm that sequentially checks each element of a list until a match is found or the entire list has been searched.
What is Insertion Sort?
A sorting algorithm that builds the final sorted array one item at a time by repeatedly inserting the next element into its correct position within the already sorted portion of the array.
What is Selection Sort?
A sorting algorithm that repeatedly finds the minimum element from the unsorted portion of the array and places it at the beginning.
What is an ArrayList?
A resizable array implementation of the List interface in Java.
What is an Index?
The position of an element within an array or ArrayList, starting from 0.
What is a Sublist?
A contiguous portion of a list or array.
How is Binary Search applied in real-world scenarios?
Searching for a word in a dictionary, finding a contact in a sorted phone book, searching for a value in a sorted database index.
How is Merge Sort applied in real-world scenarios?
External sorting of large datasets that don't fit in memory, sorting large files, used in various sorting algorithms in databases.
How is Linear Search applied in real-world scenarios?
Searching for an item in a small, unsorted list, finding a specific file in a directory.
How is Insertion Sort applied in real-world scenarios?
Sorting a hand of playing cards, sorting small datasets, used as a subroutine in more complex sorting algorithms.
How is Selection Sort applied in real-world scenarios?
Although not very efficient, it can be used in scenarios where memory usage is a primary concern due to its in-place sorting nature.
What are real-world applications of recursion?
File system traversal, parsing complex data structures (like XML or JSON), implementing tree-based algorithms, and solving problems that can be broken down into smaller, self-similar subproblems.
How are sorting algorithms used in databases?
Sorting is essential for indexing data, optimizing query performance, and presenting data in a structured manner.
How are searching algorithms used in databases?
Searching algorithms are used to efficiently locate specific records within a database, enabling quick retrieval of information.
How are sorting algorithms used in search engines?
Search engines use sorting algorithms to rank search results based on relevance, ensuring that the most relevant results appear at the top of the page.
How are searching algorithms used in search engines?
Search engines use searching algorithms to quickly locate web pages that match a user's search query.
What does the following code output?
java
ArrayList<Integer> arr = new ArrayList<>(Arrays.asList(5, 2, 8, 1, 9));
Collections.sort(arr);
System.out.println(arr);
[1, 2, 5, 8, 9]
Identify the error in the following code:
java
public static int recursiveBinarySearch(ArrayList<Integer> array, int n, int left, int right) {
int middle = (left + right) / 2;
if (left > right) { return -1; }
else if (n == array.get(middle)) { return middle; }
else if (n < array.get(middle)) { recursiveBinarySearch(array, n, left, middle - 1); }
else if (n > array.get(middle)) { recursiveBinarySearch(array, n, middle + 1, right); }
}
The recursive calls don't return a value. Should be return recursiveBinarySearch(...).
What does the following code output?
java
ArrayList<Integer> arr = new ArrayList<>(Arrays.asList(5, 2, 8, 1, 9));
recursiveInsertionSort(arr, 0);
System.out.println(arr);
Assuming recursiveInsertionSort is correctly implemented.
[1, 2, 5, 8, 9]
What does the following code output?
java
ArrayList<Integer> arr = new ArrayList<>(Arrays.asList(5, 2, 8, 1, 9));
recursiveSelectionSort(arr, 0);
System.out.println(arr);
Assuming recursiveSelectionSort is correctly implemented.
[1, 2, 5, 8, 9]
What does the following code output?
java
ArrayList<Integer> arr = new ArrayList<>(Arrays.asList(5, 2, 8, 1, 9));
mergeSort(arr);
System.out.println(arr);
Assuming mergeSort is correctly implemented.
[1, 2, 5, 8, 9]
What does the following code output?
java
ArrayList<Integer> arr = new ArrayList<>(Arrays.asList(5, 2, 8, 1, 9));
int index = recursiveLinearSearch(arr, 8, 0);
System.out.println(index);
2
What does the following code output?
java
ArrayList<Integer> arr = new ArrayList<>(Arrays.asList(1, 2, 5, 8, 9));
int index = recursiveBinarySearch(arr, 5, 0, arr.size() - 1);
System.out.println(index);
2
Identify the error in the following code:
java
public static int recursiveLinearSearch(ArrayList<Integer> array, int n, int startingIndex) {
if (array.get(startingIndex) == n) { return startingIndex; }
else if (startingIndex == array.size() - 1) { return -1; }
else { recursiveLinearSearch(array, n, startingIndex); }
}
The recursive call does not increment startingIndex, leading to infinite recursion. Should be recursiveLinearSearch(array, n, startingIndex + 1).
What does the following code output?
java
ArrayList<Integer> arr = new ArrayList<>(Arrays.asList(5, 2, 8, 1, 9));
int index = recursiveLinearSearch(arr, 10, 0);
System.out.println(index);
-1
What does the following code output?
java
ArrayList<Integer> arr = new ArrayList<>(Arrays.asList(1, 2, 5, 8, 9));
int index = recursiveBinarySearch(arr, 10, 0, arr.size() - 1);
System.out.println(index);
-1