Building Java Programs: A Back to Basics Approach (4th Edition)
4th Edition
ISBN: 9780134322766
Author: Stuart Reges, Marty Stepp
Publisher: PEARSON
expand_more
expand_more
format_list_bulleted
Videos
Expert Solution & Answer
Chapter 12, Problem 22E
Explanation of Solution
Method definition:
/* Prints all ways to express n as a sum of squares of unique integers with precondition: n >= 0*/
//method definition
public static void printSquares(int n)
{
//define the integer sets
Set<Integer> chosen = new TreeSet<Integer>();
//call the method explore
explore(n, 1, chosen);
}
/* all ways are explored to form n as a sum of squares of integers starting
from the given min value and storing the chosen results with the given set*/
//method definition
private static void explore(int n, int min, Set<Integer> chosen)
{
//validate the value of n to be zero
if (n == 0)
{
//method call that is base case when sum has reached n
printHelper(chosen);
}
else
{
// All possible combination are tried
//validate the choices upto sqrt(n)
int max = (int)Math...
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Write a recursive method that gets three parameters as input: an array of integers called nums, an integer called index,and an integer called The purpose of this method is to return true if value is stored in the array starting at nums[index]. That is, you have to check if value is equal to nums[index] or nums[index +1] or nums[index +2 ] …. nums[nums.length -1]. Do not use loops.(java code)
Write a method printSquares that uses recursive backtracking to find all ways to express an integer as a sum of squares of unique positive integers. For example, the call of printSquares(200); should produce the following output:1^2 + 2^2 + 3^2 + 4^2 + 5^2 + 8^2 + 9^21^2 + 2^2 + 3^2 + 4^2 + 7^2 + 11^21^2 + 2^2 + 5^2 + 7^2 + 11^21^2 + 3^2 + 4^2 + 5^2 + 6^2 + 7^2 + 8^21^2 + 3^2 + 4^2 + 5^2 + 7^2 + 10^22^2 + 4^2 + 6^2 + 12^22^2 + 14^23^2 + 5^2 + 6^2 + 7^2 + 9^26^2 + 8^2 + 10^2Some numbers (such as 128 or 0) cannot be represented as a sum of squares, in which case your method should produce no output. Keep in mind that the sum has to be formed with unique integers. Otherwise you could always find a solution by adding 1^2 together until you got to whatever number you are working with.As with any backtracking problem, this one amounts to a set of choices, one for each integer whose square might or might not be part of your sum. In many of our backtracking problems we store the choices in…
The nth harmonic number is defined non-recursively as H(n) = 1+1/2+1/3+1/4+⋯+1/n Come up with a recursive definition and use it to guide you to write a method definition for a double-valued method named “harmonic” that accepts an int parameter n and recursively calculates and returns the nth harmonic number. Write a test program that displays the harmonic numbers, H(n), for n = 1,2,3,⋯,10.
Chapter 12 Solutions
Building Java Programs: A Back to Basics Approach (4th Edition)
Ch. 12.1 -
What is recursion? How does a recursive method...Ch. 12.1 - Prob. 2SCPCh. 12.1 - Prob. 3SCPCh. 12.1 - Prob. 4SCPCh. 12.1 - Prob. 5SCPCh. 12.1 - Prob. 6SCPCh. 12.1 - Prob. 7SCPCh. 12.2 - Prob. 8SCPCh. 12.2 -
What would be the effect if the code for the...Ch. 12.2 -
What would be the effect if the code for the...
Ch. 12.3 - Prob. 11SCPCh. 12.3 - Prob. 12SCPCh. 12.3 - Prob. 13SCPCh. 12.3 - Prob. 14SCPCh. 12.3 - Prob. 15SCPCh. 12.3 - Prob. 16SCPCh. 12.3 - Prob. 17SCPCh. 12.3 - Prob. 18SCPCh. 12.3 - Prob. 19SCPCh. 12.4 - Prob. 20SCPCh. 12.4 - Prob. 21SCPCh. 12.5 - Why is recursion an effective way to implement a...Ch. 12.5 - Prob. 23SCPCh. 12.5 - Prob. 24SCPCh. 12.5 - Prob. 25SCPCh. 12.5 - Prob. 26SCPCh. 12.5 - Prob. 27SCPCh. 12.5 - Prob. 28SCPCh. 12 - Prob. 1ECh. 12 - Write a method called writeNums that takes an...Ch. 12 - Write a method called writeSequence that accepts...Ch. 12 - Write a recursive method called doubleDigits that...Ch. 12 - Prob. 5ECh. 12 - Prob. 6ECh. 12 - Prob. 7ECh. 12 - Write a recursive method called multiplyEvens that...Ch. 12 - Prob. 9ECh. 12 - Prob. 10ECh. 12 - Prob. 11ECh. 12 - Write a recursive method called isReverse that...Ch. 12 - Prob. 13ECh. 12 - Prob. 14ECh. 12 - Prob. 15ECh. 12 - Prob. 16ECh. 12 - Prob. 17ECh. 12 - Prob. 18ECh. 12 - Prob. 19ECh. 12 - Prob. 20ECh. 12 - Prob. 21ECh. 12 - Prob. 22E
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, computer-science and related others by exploring similar questions and additional content below.Similar questions
- Write a method printSquares that uses recursive backtracking to find all ways to express an integer as a sum of squares of unique positive integers. For example, the call of printSquares(200); should produce the following output:1^2 + 2^2 + 3^2 + 4^2 + 5^2 + 8^2 + 9^21^2 + 2^2 + 3^2 + 4^2 + 7^2 + 11^21^2 + 2^2 + 5^2 + 7^2 + 11^21^2 + 3^2 + 4^2 + 5^2 + 6^2 + 7^2 + 8^21^2 + 3^2 + 4^2 + 5^2 + 7^2 + 10^22^2 + 4^2 + 6^2 + 12^22^2 + 14^23^2 + 5^2 + 6^2 + 7^2 + 9^26^2 + 8^2 + 10^2Some numbers (such as 128 or 0) cannot be represented as a sum of squares, in which case your method should produce no output. Keep in mind that the sum has to be formed with unique integers. Otherwise you could always find a solution by adding 1^2 together until you got to whatever number you are working with.As with any backtracking problem, this one amounts to a set of choices, one for each integer whose square might or might not be part of your sum. In many of our backtracking problems we store the choices in…arrow_forwardWrite a recursive method that gets two parameters as input: an array of integers called nums and an integer called index. The purpose of this method is to return the following: nums[index] * nums[index+ 1] * nums[index+ 2] * .. nums[nums.length-1]. Do not use loops. (java code)arrow_forwardWrite a recursive method that gets three parameters as input: an array of integers called nums, an integer called index, and an integer called value. The purpose of this method is to count how many times value appears in the array starting at nums[index]. Do not use loops. (Java code)arrow_forward
- Do not use static variables to implement recursive methods. USING JAVA: // P6 public static int countSubstrings(String s1, String s2) { } Write a recursive method countSubstrings that counts the number of non-overlapping occurrences of a string s2 in a string s1. Use the method indexOf() from String class. As an example, with s1=”abab” and s2=”ab”, countSubstrings returns 2. With s1=”aaabbaa” and s2=”aa”, countSubstrings returns 2. With s1=”aabbaa” and s2=”AA”, countSubStrings returns 0. Show the output on the following strings: s1 = “Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities. Java applications are typically compiled to bytecode (class file) that can run on any Java Virtual Machine (JVM) regardless of computer architecture.…arrow_forwardWrite a recursive method called doubleDigits that accepts an integer n as a parameter and returns the integer obtained by replacing every digit of n with two of that digit. For example, doubleDigits(348) should return 334488. The call doubleDigits(0) should return 0. Calling doubleDigits on a negative number should return the negation of calling doubleDigits on the corresponding positive number; for example, doubleDigits(–789) should return –778899.arrow_forwardYou will be given an array A of length n. Write a method to calculate the following value of X using recursion. X = Ao x 7° + A1 x 7' + Az × 7² +. +An-1 x 7"-1 • The recursion can have any number of parameters. You can't use loops or math.pow() or a separate recursive function to calculate 7". The return type should be integer. • The range for n is 1arrow_forwardWrite a RECURSIVE method called “sequence” that takes a single int parameter (n) and returns the int value of the nth element of the sequence S = 2, 4, 6, 12, 22, 40, 74, 136, 250, 460, … Where S is defined by the recursive formula: For n >= 0S(0) = 2; // Base case 1S(1) = 4; // Base case 2S(2) = 6; // Base case 3S(N) = 2 * ( S(N-1)/2 + S(N-2)/2 + S(N-3)/2)arrow_forwardWe want to create a recursive method called numbers. This method is suppose to create the following sample output numbers(10) should display 10 9 8 7 6 5 4 3 2 1 0 numbers(5) should display 5 4 3 2 1 0 Fill in the blank so that the method generates the desired output public static void numbers(int a) { if (_1__ ___2___ __3___) <----- base case return; System.out.print(___4___ + " "); ___5___(___6___ ___7___ _____8____); <--- recursive case }arrow_forwardWrite a static recursive method called mrecursiv that displays all of the permutations of the characters in a string passed to the method as its argument. For example, the character sequence abc has the following permutations: acb, bac, bca, cab, cba. Then Write a static method called getInput that get an input string from the user and passed it to the mrecursiv method written above in a method call.arrow_forwardWrite a recursive method called reverseString() that takes in a string as a parameter and returns the string in reversed order. The main method is provided to read a string from the user and call the reverseString() method. Use Java. Ex: If the input of the program is: Hello the reverseString() method returns and the program outputs: Reverse of "Hello" is "olleH". Ex: If the input of the program is: Hello, world! the reverseString() method returns and the program outputs: Reverse of "Hello, world!" is "!dlrow ,olleH". Hint: Move the first character to the end of the returning string and pass the remaining sub-string to the next reverseString() method call. import java.util.Scanner; public class LabProgram { /* TODO: Write recursive reverseString() method here. */public static void main(String[] args) {Scanner scnr = new Scanner(System.in);String input, result;input = scnr.nextLine();result = reverseString(input); System.out.printf("Reverse of \"%s\" is \"%s\".", input, result);}}arrow_forwardWrite a recursive method that takes as parameter as array of type double (num) and the length of the array (len). The method should display the square root of numbers that are greater than 10.0 in the array. The method prototype is: public static void display(double [] num, int len); You may use sqrt method that is defined in the Math class.arrow_forwardWrite a recursive method that returns thelargest integer in an array. Write a test program that prompts the user to enter alist of eight integers and displays the largest element.arrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_ios
Recommended textbooks for you
Database System ConceptsComputer ScienceISBN:9780078022159Author:Abraham Silberschatz Professor, Henry F. Korth, S. SudarshanPublisher:McGraw-Hill Education
Starting Out with Python (4th Edition)Computer ScienceISBN:9780134444321Author:Tony GaddisPublisher:PEARSON
Digital Fundamentals (11th Edition)Computer ScienceISBN:9780132737968Author:Thomas L. FloydPublisher:PEARSON
C How to Program (8th Edition)Computer ScienceISBN:9780133976892Author:Paul J. Deitel, Harvey DeitelPublisher:PEARSON
Database Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781337627900Author:Carlos Coronel, Steven MorrisPublisher:Cengage Learning
Programmable Logic ControllersComputer ScienceISBN:9780073373843Author:Frank D. PetruzellaPublisher:McGraw-Hill Education
Database System Concepts
Computer Science
ISBN:9780078022159
Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan
Publisher:McGraw-Hill Education
Starting Out with Python (4th Edition)
Computer Science
ISBN:9780134444321
Author:Tony Gaddis
Publisher:PEARSON
Digital Fundamentals (11th Edition)
Computer Science
ISBN:9780132737968
Author:Thomas L. Floyd
Publisher:PEARSON
C How to Program (8th Edition)
Computer Science
ISBN:9780133976892
Author:Paul J. Deitel, Harvey Deitel
Publisher:PEARSON
Database Systems: Design, Implementation, & Manag...
Computer Science
ISBN:9781337627900
Author:Carlos Coronel, Steven Morris
Publisher:Cengage Learning
Programmable Logic Controllers
Computer Science
ISBN:9780073373843
Author:Frank D. Petruzella
Publisher:McGraw-Hill Education
Introduction to Big O Notation and Time Complexity (Data Structures & Algorithms #7); Author: CS Dojo;https://www.youtube.com/watch?v=D6xkbGLQesk;License: Standard YouTube License, CC-BY