I need to create an algorithm that finds the common element(s) in all arrays that has a signature of public Comparable[] findCommonElements(Object[] collection) that has an efficiency of at most O(knlogn), uses a query array, and accepts as input a collection of arrays. I am aware my time would be better spent learning how to use array lists and hash sets, but I am supposed to use concepts already covered, and these have not been.
I feel like this code should work, but it is returning null for the array of common elements. Which means it obviously is not working correctly. I am also likely going to need implementing the sort algorithm, but I wanted to get the part of finding the common elements set first.
public class CommonElements2<T extends Comparable<T>>
{
Comparable[] tempArr;
Comparable[] common;
Comparable[] queryArray;
/*
sort algorithm goes here
*/
public Comparable[] findCommonElements(Object[] collections)
I have two ArrayLists and I want to compare them for common elements, and based on the result I want to update the first Arraylist to only have these elements. sort of like the opposite of RemoveAll() which removes elements in common and keep the ones that are unique. so far I thought of using for loop and .contains() in case it was fault,element not present, remove from list. but I was wondering in what other ways, perhaps APIs i can use to do that?
I am using a IN clause in Oracle DB to pass a collection of custId to retrieve the customer details. If it was 10 or 50 custId's as a collection in IN clause it works fine. But if the collection grows bigger to 500 or 1000 then it is pretty slow to load the JSP page with the customer details.
Here is the query:-
select CustName, CustAge, CustCity, CustPin from CUSTOMER where custId IN (....)
The list of custId that is passed through Hibernate query.setParameterList()
How to optimize this query to make sure it displays the customer details faster even if the collection of elements which we pass is huge?
In attempting to find the greatest common divisor (gcd) of two integers, n1 and n2, whereas k is a possible gcd and gcd is initialized to 1, the following code has been entered:
for (int k = 2; k <= n1 && k <= n2; k++) { if ( n1 % 2 == 0 && n2 % 2 == 0) gcd= k; }
When asked to change the previous line of code to this:
for (int k = 2; k <= n1 / 2 && k < n2 / 2; k++){
the questions states this revision is wrong and to find the reason.....well, I've changed it, entered "3" (per the answer key) for n1 and n2....
now I can see logically where k (2 in this example) is not <= n1/2, which is 3/2 or 1, since we're dealing w/integers, yet when I compile and run, my answer is indeed, gcd = 1. However, since this is a Boolean expression where && is being used, since the first portion evaluates to "false", the 2nd portion isn't executed and thus my result of 1?...... loops are throwing me for one, for sure....
So in this program, which is a grading program, I am trying to compare all the students averages to find who has the highest one and list the grades and the student's names from least to greatest. Yes, I see there are other problems in the program but it is nowhere near finished.
import java.util.Scanner; public class Main { public static void main(String[] args) { String[] studentName = new String[20]; int[] studentAverage = new int[20]; Scanner input = new Scanner(System.in);
Is there any way to find how many number of elements are landing in same bucket in HashSet. I know Reflection could be one way but i am not able to design a program for that.
I need to write a java program to find the index of the element whose value is the sum of the remaining elements. Recently I have been asked this question in an Interview which I couldnt solve properly.
I am taking the Class Algorithms and Datastructures and got an assignment for Lab that really throws me off. The goal is to create an Array out of a given CSV file, implement several Methods that get the size of array, etc.
I am still stuck in the first part where the CSV has to be imported into the Array. My problem is that I need a mechanism that figures out the needed size for the Array, creates the array, and only then transfers the data from the CSV.
The list consists of the following wifi related values:
MAC-Adress, SSID, Timestamp, Signalstrength.
These are on the list, separated by comma. The Columns are each of these, and the rows are the four types of values making up the information on a certain wifi network.
The catch is, we are not allowed to use any of the following:
java.util.ArrayList java.util.Arrays and any class out of java.util.Collection.
So far I used the BufferedReader to read in the file and tried to implement the array, but I get an arrayindexoutofboundsexception.
Below is my Code (Its still an active construction zone):
public class WhatsThere { public WhatsThere(String wifiscan) throws IOException { } public static void main(String[] args) throws IOException { // WhatsThere Liste = new WhatsThere(String wifiscan); String[][] arrayListe = new String[0][0];
import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class array { public static void main(String[] args)
[Code] ...
Is there a way to write this, where, alpha is one array.
Write a program that declares an array "alpha" of 50 elements of type "double". Initialize the array so that the first 25 elements are equal to the square of the index variable and the last 25 elements are equal to three times the index variable. Output the array so that 10 elements per line are printed.
If I have an array of 50 integers, can I break that to read in lines of 10?
I am trying to make a 2d array that keeps track of comparison counts. what I have so far works ok but writes over the previous elements with 0. can't seem to find where I am re-initializing the previous elements.
//this is one of my fill sort arrays
public void fillSelectionArray(int index, long countSum) { //rand = new Random( ); //for ( int i = 0; i < listsize; i++) { selectionList[ index -1] = countSum; // }
Which of these is not a real differentiator for programming languages:
a) Object-oriented / Process-Oriented b) Interactive / Automated c) Interpreted / Compiled d) Strongly-Typed / Weakly-Typed e) All of the above f) B and C g) B and D
Almost all support OOP, Interactive/Automated, Interpreted/Compiled but not sure about Strongly typed/Weakly typed.
I have developed a web portal using jsp and struts 2. I have approximately 10 JSP pages which looks exactly the same and have two text areas and two hidden fields. All 10 pages are exactly the same except for hidden field value. Can't i have a single common jsp page. How can i achieve it. A sample page i am attaching...
I am using the following regex - [a-zA-Z0-9]{9,18} which means I can use alphabets and numbers with minimum length as 9 and maximum length as 18.It should not take special characters.
It takes values like ADV0098890 etc. but it is also taking ADV0098890[] which is wrong.
when a new object is created in Java it follows the idiom:
Object obj = new Object(); where the Object() constructor matches the object type Object.
But what if it doesn't? I understand from the Oracle Docs on creating objects and polymorphism that the constructor must be in that object's class or one of its subclasses. However, suppose we wanted to declare a new stack. My first instinct would be:
Stack s1 = new Stack(); But I assume it's valid to do it this way, too:
Object s2 = new Stack(); // Is there a difference here? What are we really saying about s2? I'm guessing s2 is simply an empty stack, but only has access to the Object class methods? I'm not sure why someone would ever do this, but I want to solidify my understanding of the Java hierarchy. Are there really any circumstances where someone would use a subclass's constructor when creating a new object?
I have two different "business objects", and they have multiple attributes in common(around 25 I believe, all of which are simply a String). Basically, these objects are used for documentation purposes on the same file.
The program can choose to update a given Document at any point in time, even if changes haven't been made to existing version. So what I'm trying to do, is check to see if these attributes differ any between the two files(the exisitng copy, and the new request). If so, I'll update...else I simply throw out the request. The workload can be rather intense at times so I don't want to bog down the system anymore then necessary.
Simply pulling down every attribute for each and comparing seems like a lot of overhead, any more efficient way to achieve these results?
The final map would have all the values from Map A as a key and the values from Map B as values in the Final Map. Is there a way to do this using Java?
I have done one program, that calculates the Least Common Multiple. The idea is to use WindowsBuilder on Ecplise in order to run it in a separate window. But when I started nothing happens. The code is:
Just wondering what could I do to make it happen. One thing came up on my mind - this is that need to connect the button with the function of the method, but still not sure will work.
I am working with Netbeans 8.0 and JSF2.2. I am trying to create a web site that has a common header, footer, and menu. The only part that would be dynamic is the content. So here goes...
1) I need a common template that has 4 parts, Header, Footer, Menu, Content 2) The header, footer and menu are to be in a separate files of which are called from the main template 3) The content will change based on the menu item changed 4) The menu has to change the content section only
I know how to do this in HTML but I am trying to set up some thing in JSF to learn more on JSF pages. All I am looking for is an example that I can follow along with having the multiple pages as well having the menu change the content (I have done a ton of internet searching but nothing really fits the bill).
This is the code I have currently.
Index (Main Template) <?xml version='1.0' encoding='UTF-8' ?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://xmlns.jcp.org/jsf/facelets" xmlns:h="http://xmlns.jcp.org/jsf/html">
"What happens if you modify the common object references in these lists, myArrList and urArrList ? We have 2 cases here: In the first one, you reassign the object reference using either of the lists. In this case, the value in the second list will remain unchanged.In the second case, you modify the internals of any of the common list elements - in this case, the change will be reflected in both lists."
I have written the following code, which tests the first case mentioned above, and i get the output as expected: myarrList remains unchanged. How can i test the second case ? My thoughts are ....'second case is untestable the following code, because String is immutable. I need to use StringBuilder or something else to write code for test of second case mentioned'.
ArrayList<String> myarrList = new ArrayList<>(); myarrList.add("one"); myarrList.add("two"); ArrayList<String> urarrList = new ArrayList<>(); urarrList.add("three"); urarrList.add("four"); System.out.println("ArrayLists setup");
My program is user input 20 char and the program will print the most common. So I use another int arr which count the number appears in the original array. i know its not so Effective but I don't know why it run but it stop in the middle. I got this code :
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 20 at Ex2.common(Ex2.java:39) at Ex2.main(Ex2.java:23)
import java.util.Scanner; class Ex2 { public static void main(String[] arg) { Scanner reader = new Scanner (System.in); char[] arr=new char[20]; System.out.println("Please enter 20 chars:"); for (int i=0;i<20;i++)
I have small project to be implemented in Java, which, expected the management of a parking.
The project has a class abstract Vehicle, whence derive three classes: Car, Motorcycle, Heavy Vehicles; the cost estimated time for the 3 types of vehicles are: 2€ for Cars, 1€ for Motorcycle and 5€ for H.V.
In addition, in class Ticket will be stored the arrival time of the customer and the characteristics of his vehicle.
Finally, in the class Parking(which provides 80 places available), here it should be added the various types of vehicles.
Now, I though of using an Collection, as Set.. So that they can not, two Vheicle with same license plate.
