Java Assignment Solution: Solve Algorithm Problems Efficiently

Instructions

Objective

Write a program to solve algorithm problems in Java language. Java is a powerful and widely-used programming language known for its portability and robustness. The assignment might involve implementing sorting algorithms, data structures, or solving mathematical challenges. By understanding the principles of object-oriented programming and mastering Java syntax, you can develop efficient and elegant solutions. Completing a Java assignment will not only enhance your coding skills but also deepen your understanding of algorithms and their applications in real-world scenarios.

Requirements and Specifications

Source Code

PROBLEM 1

import java.util.Random; public class Problem1 { public static void main(String[] args) throws Exception { // First, create an empty array of 10 elements int array[] = new int[10]; // Now, create a random object Random random = new Random(); // Now, fill with random integers between 0 and 1000 System.out.print("The array is: "); for(int i = 0; i < 10; i++) { array[i] = random.nextInt(1000); System.out.print(array[i] + " "); } System.out.println(""); // Print element at an even index System.out.print("Elements at even index: "); for(int i = 0; i < 10; i++) { if(i%2 == 0) // index is event { System.out.print(array[i] + " "); } } System.out.println(""); // Even elements System.out.print("Even elements: "); for(int i = 0; i < 10; i++) { if(array[i]%2 == 0) // element is even { System.out.print(array[i] + " "); } } System.out.println(""); // Reverse order System.out.print("Elements in reverse order: "); for(int i = 0; i < 9; i++) { System.out.print(array[10-i-1] + " "); } System.out.println(""); // First and last System.out.println("The first element is: " + array[0]); System.out.println("The last element is: " + array[9]); // Get min and max int min = array[0]; int max = array[0]; for(int i = 1; i < 10; i++) { if(array[i] < min) // current element is lower than current min { min = array[i]; } if(array[i] > max) // current element is bigger than current max { max = array[i]; } } System.out.println("The min element is: " + min); System.out.println("The max element is: " + max); // Create variable to store sum and alternating sum int sum = 0, alternating_sum = 0; for(int i = 0; i < 9; i++) { sum += array[i]; if(i%2 == 0) // if index is event, add element to alternating sum { alternating_sum += array[i]; } else { // index is odd, subtract element to alternating sum alternating_sum -= array[i]; } } System.out.println("The sum is: " + sum); System.out.println("The alternating sum is: " + alternating_sum); } }

PROBLEM 2

import java.util.ArrayList; import java.util.List; import java.util.Scanner; // Create a private class to stoe the label and the value class Value { String label; int value; public Value(String label, int value) { this.label = label; this.value =value; }; } public class Problem2 { static void printElement(Value value, int n_asterisks) { System.out.print(value.label + " "); for(int i = 0; i < n_asterisks; i++) { System.out.print("*"); } System.out.println(""); } public static void main(String[] args) throws Exception { // Create Scanner to read user's input Scanner sc = new Scanner(System.in); // Create a list of Values List values = new ArrayList(); // Variable to store the max value // Variables to receive label and value from user String label; int value; String input; // Ask user for values until s/he enters an empty line while(true) { System.out.print("Enter label and value separated by space (e.g: Egypt 10): "); input = sc.nextLine(); // if input is empty, exit loop if(input.length() == 0) { break; } // Split String[] data = input.split(" "); try { label = data[0]; value = Integer.valueOf(data[1]); // Create value object Value val = new Value(label, value); // Add to list values.add(val); } catch(Exception ex) // if we get an exception, it must be because user entered a non-integer for the value { System.out.println("Please enter a valid label and value."); } } // Now, get max value int max_value = values.get(0).value; for(int i = 1; i < values.size(); i++) { if(values.get(i).value > max_value) { max_value = values.get(i).value; } } // Now, print for(int i = 0; i < values.size(); i++) { // Calculate number of asteriks for this value int n_asterisks = values.get(i).value*40/max_value; // Display printElement(values.get(i), n_asterisks); } } }

PROBLEM 3

import java.util.ArrayList; import java.util.List; import java.util.Scanner; // Create class to store the names and zip. This class is named Person class Person { private String firstName; private String lastName; private int zip; public Person(String firstName, String lastName, int zip) { this.firstName = firstName; this.lastName = lastName; this.zip = zip; } // getters public String getFirstName() {return firstName;} public String getLastName() {return lastName;} public int getZipCode() {return zip;} } public class Problem3 { public static void main(String[] args) throws Exception { // Create Scanner Scanner sc = new Scanner(System.in); // Number of input to be read int N = 2; // List to store inputs List persons = new ArrayList(); // Read String input, firstName, lastName; int zip; for(int i = 0; i < N; i++) { input = sc.nextLine(); String[] data = input.split("\t"); firstName = data[0]; lastName = data[1]; zip = Integer.valueOf(data[2]); // Create Person object Person person = new Person(firstName, lastName, zip); // Add to list persons.add(person); } System.out.println(""); // Now, print System.out.println(String.format("%-10s %25s %25s", "First Name", "Last Name", "ZIP Code")); System.out.println(String.format("%-10s %25s %25s", "----------", "---------", "--------")); for(Person p: persons) { System.out.println(String.format("%-10s %25s %25d", p.getFirstName(), p.getLastName(), p.getZipCode())); } } }

PROBLEM 4

import java.util.Scanner; public class Problem4 { static void printSeats(int[][] seats, int N) { // This function prints seats for(int i = 0; i < N; i++) { for(int j = 0; j < N; j++) { System.out.print(String.format("%5d", seats[i][j])); } System.out.println(""); } } static void displayMenu() { /* * This function prints the menu to the user */ System.out.println("1) Select seat by position"); System.out.println("2) Select seat by price"); System.out.println("3) Exit"); } static int getInteger(String message, int lb, int ub, Scanner sc) { /* * This function will ask user for a positive integer * If the user enters a valid input, the function will display * an error message and reprompt */ int value; while(true) { try{ System.out.print(message); value = Integer.valueOf(sc.nextLine()); if(value >= lb && value <= ub) { return value; } else { System.out.println("Please enter a number between " + lb + " and " + ub + "."); } } catch(Exception ex) { System.out.println("Please enter a valid number."); } } } public static void main(String[] args) throws Exception { // Create Scanner scanner sc = new Scanner(System.in); // Define size of theater (we assumed it squared, so same number of rows and columns) int N = 10; // Create 2-D array to store seats int seats[][] = new int[N][N]; // Initialize seats for(int i = 0; i < N; i++) { for(int j = 0; j < N; j++) { if(i < 3) { seats[i][j] = 10; } else if(i >= 3 && i < 6) { seats[i][j] = 20; } else if(i >= 6 && i < 8) { seats[i][j] = 30; } else if(i == 8) { seats[i][j] =40; } else { seats[i][j] = 50; } } } // Now, ask user for a seat or price int option; while(true) { printSeats(seats, N); System.out.println(""); displayMenu(); // Ask for option option = getInteger("Enter option: ", 1, 3, sc); if(option == 1) // enter seat by row and column { int row = getInteger("Enter row (1-" + N + "): ", 1, 10, sc); int column = getInteger("Enter column (1-" + N + "): ", 1, 10, sc); // Check if seat is availab if(seats[row-1][column-1] != 0) { System.out.println("You purchased the seat located at (" + row + "," + column + ")."); seats[row-1][column-1] = 0; } else { System.out.println("Sorry, this seat is already taken."); } } else if(option == 2) { int price = getInteger("Enter price: ", 10, 50, sc); // Check if there is a seat with that price available boolean found = false; for(int i = 0; i < N; i++) { for(int j = 0; j < N; j++) { if(seats[i][j] == price) { found = true; seats[i][j] = 0; System.out.println("You purchased the seat located at (" + (i+1) + "," + (j+1) + ")."); break; } } if(found) { break; } } if(!found) // no seat found { System.out.println("Sorry, there is not seat available with that price."); } } else if(option == 3) { System.out.println("Good Bye!"); break; } } } }

PROBLEM 5

import java.util.Random; import java.util.Scanner; public class Problem5 { static void printArray(int[][] array, int N) { // This function prints array for(int i = 0; i < N; i++) { for(int j = 0; j < N; j++) { System.out.print(String.format("%5d", array[i][j])); } System.out.println(""); } } static void displayMenu() { /* * This function prints the menu to the user */ System.out.println("1) Calculate total of data"); System.out.println("2) Calculate average of data"); System.out.println("3) Row total"); System.out.println("4) Column total"); System.out.println("5) Highest in row"); System.out.println("6) Lowest in row"); System.out.println("7) Highest in column"); System.out.println("8) Lowest in column"); System.out.println("9) Exit"); } static int getInteger(String message, int lb, int ub, Scanner sc) { /* * This function will ask user for a positive integer * If the user enters a valid input, the function will display * an error message and reprompt */ int value; while(true) { try{ System.out.print(message); value = Integer.valueOf(sc.nextLine()); if(value >= lb && value <= ub) { return value; } else { System.out.println("Please enter a number between " + lb + " and " + ub + "."); } } catch(Exception ex) { System.out.println("Please enter a valid number."); } } } // Operations static int getTotal(int[][] array) { /* * This function calculates the sum of all values in the 2-D array */ int N = array.length; int sum = 0; for(int i = 0; i < N; i++) { for(int j = 0; j < N; j++) { sum += array[i][j]; } } return sum; } static double getAverage(int[][] array) { /* * This function calculates the average of all values in the 2-D array */ int N = array.length; int sum = getTotal(array); double average = (double)sum/(N*N); return average; } static int getRowTotal(int[][] array, int row) { /* * Given the array, its size and the row id, this function calculates the sum of that row * */ int N = array.length; int sum = 0; for(int column = 0; column < N; column++) { sum += array[row][column]; } return sum; } static int getHighestInRow(int[][] array, int row) { int N = array.length; // Select the first element in the row as the highest int highest = array[row][0]; for(int col = 1; col < N; col++) { if(array[row][col] > highest) { highest = array[row][col]; } } return highest; } static int getLowestInRow(int[][] array, int row) { int N = array.length; // Select the first element in the row as the lowest int lowest = array[row][0]; for(int col = 1; col < N; col++) { if(array[row][col] < lowest) { lowest = array[row][col]; } } return lowest; } static int getHighestInColumn(int[][] array, int column) { int N = array.length; // Select the first element in the column as the highest int highest = array[0][column]; for(int row = 1; row < N; row++) { if(array[row][column] > highest) { highest = array[row][column]; } } return highest; } static int getLowestInColumn(int[][] array, int column) { int N = array.length; // Select the first element in the column as the lowest int lowest = array[0][column]; for(int row = 1; row < N; row++) { if(array[row][column] < lowest) { lowest = array[row][column]; } } return lowest; } static int getColumnTotal(int[][] array, int col) { /* * Given the array, its size and the column id, this function calculates the sum of that column * */ int N = array.length; int sum = 0; for(int row= 0; row< N; row++) { sum += array[row][col]; } return sum; } public static void main(String[] args) throws Exception { // Create Scanner Scanner sc = new Scanner(System.in); // create random object Random random = new Random(); // Define size of array (we assumed it squared, so same number of rows and columns) int N = 20; // Create 2-D array to store data int data[][] = new int[N][N]; // Initialize data with random integers between 1 and 100 for(int i = 0; i < N; i++) { for(int j = 0; j < N; j++) { data[i][j] = random.nextInt(100); } } // Now, ask user for menu option int option; while(true) { printArray(data, N); System.out.println(""); displayMenu(); // Ask for option option = getInteger("Enter option: ", 1, 9, sc); if(option == 1) // Calculate total { int total = getTotal(data); System.out.println("The sum of all elements in the data is: " + total); } else if(option == 2) // average { double avg = getAverage(data); System.out.println(String.format("The average of all values is: %.2f", avg)); } else if(option == 3) { // row total int row = getInteger("Enter row: ", 1, N, sc); int total = getRowTotal(data, row-1); System.out.println("The sum of all elements in row " + row + " is: " + total); } else if(option == 4) { // column total int column= getInteger("Enter column: ", 1, N, sc); int total = getColumnTotal(data, column-1); System.out.println("The sum of all elements in column " + column + " is: " + total); } else if(option == 5) { // highest in row int row = getInteger("Enter row: ", 1, N, sc); int total = getHighestInRow(data, row-1); System.out.println("The highest element in row " + row + " is: " + total); } else if(option == 6) { // lowest in row int row = getInteger("Enter row: ", 1, N, sc); int total = getLowestInRow(data, row-1); System.out.println("The lowest element in row " + row + " is: " + total); } else if(option == 7) { // highest in column int column = getInteger("Enter column: ", 1, N, sc); int total = getHighestInColumn(data, column-1); System.out.println("The highest element in column " + column + " is: " + total); } else if(option == 8) { // lowest in column int column = getInteger("Enter column: ", 1, N, sc); int total = getLowestInColumn(data, column-1); System.out.println("The lowest element in column " + column + " is: " + total); } else if(option == 9) { System.out.println("Good Bye!"); break; } } } }