Create MergeSort Method Without Using Recursion
Nov 6, 2014
We are supposed to create a MergeSort method without the using recursion. Most of the code is already completed, the only thing that I believe I need are two for loops (an inner and an outter) that will make calls to the merge method. I need implementing the sort method of the merge sort algorithm without recursion, where the length of the array is a power of 2. Keep merging adjacent regions whose size is a power of 2. For ex: lengths will be 1, 2, 4, 8, 16,.
public class MergeSorter {
public static void sort(int[] a) {
//for(int i = 1; i <= a.length; i++) the parameters for the for loop are wrong.
{
merge(0,0,1,a);
merge(1,1,2,a);
merge(2,2,3,a);
[Code]...
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Mar 9, 2015
so i have this question where it wants me to create a recursion method that takes ONLY THE ARRAY as a parameter, and without using loops or static variables inside the method, and then the method returns the smallest value in that array. However, i tried making the simple if statements where i compare the first element of the array with the second element using the length of the array and decreasing it to get the next elements and compare it again by calling the recursion method, but the problem is when i call the method again, the length does not decrease, even if i store it in a variable, the variable will initialize itself again, and the length wont change.
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Jan 11, 2015
i'm trying to exit the recursion of a void method but some funny things are happening before and after the return statement.
public static void main(String args[])
{
//code
rec(x,y);
System.out.println("HEllooooooo");}
public static void rec(int x,int y)
{
try
{
System.out.println(x+" "+y+" "+check);
if(x==fx && y==fy)
[code]....
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Jun 1, 2014
I have big problem with mergesort in Java. I can't figure out why it do not works. I need write it on lists using Comparable. Here is piece of code:
Java Code:
class MergeSort{
Comparator _comparator;
List lista = new ArrayList<>();
List list_temp = new ArrayList<>();
MergeSort(Comparator comparator){
[Code] ....
I have tried everything, still no results. It's return list with random placed numbers.
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Jan 28, 2015
i have to write a method, The method receives a parameter of two-dimensional array of integers. The method returns the number of the column which has the lowest sum of the integers.I'm allowed to use only recursion! no loops allowed!-of course i need to make a private method that will sum a column as a single array and then i have to do another private method that compares the column , but it doesn't really work .
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Feb 2, 2015
I am trying to sum up the elements of an array. When I test my code the sum is always off by one. For example if I input: 20, 40,30 it gives me 89 instead of 90.
This is what I have so far:
public static void main(String[args]){
int size = kbd.nextInt();
int [] myArray = new int [size]
//user inputs the elements of array
[Code]....
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Nov 1, 2014
I am practicing some basic recursion and I was trying to solve this problem
Write a method sumTo that accepts an integer parameter n and returns the sum of the first n reciprocals. In other words:
sumTo(n) returns: 1 + 1/2 + 1/3 + 1/4 + ... + 1/n
For example, the call of sumTo(2) should return 1.5. The method should return 0.0 if passed the value 0 and should throw an IllegalArgumentException if passed a value less than 0.
This is my attempt to do it , however my output is always a 0.0 , and i do not understand why :
public static double sumTo(int n ){
if(n<0){
throw new IllegalArgumentException();
}
else if (n==0){
return 0.0;
[Code] .....
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Jan 28, 2015
Okay so here are the requirements.
Java Code:
/**
*The method creates an array list of integers and then prompts the user
* for an integer. As long as the user continues to enter anything other
* than -999, add the number to the array list.
*
* @return the array list of numbers
*/ mh_sh_highlight_all('java');
I've attempted this several times but am still struggling.
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Mar 4, 2014
I need to create a method that returns a new array containing the componentwise sum of its arguments(if length is the same). For instance, if the input arrays are {0,1, 2} and {2, 2, 3} then the output is {0+2, 1+2, 2+3}, i.e. {2,3,5}.If the input arrays have different numbers of elements, the method should return null.
I came with something like this, however i dont know how to make a copy of an array from two arrays. My code obviously wont compile. package whatever;
import java.util.Arrays;
public class hhhh {
public static void main(String[] args) {
double [] a = {1,2,3};
double [] b = {2,3,4};
[code]...
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Oct 4, 2014
I'm trying to create a simple java math question quiz using random operators, but keep sinking myself into deeper despair. The numbers must range from 0-9 and given an operator: +,-,/,*,%. Can't create a new method or use Case statements. The code isn't finished but don't want to make it any worse.
package marco;
import java.util.Scanner;
import java.util.Random;
public class Project {
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
Random rand = new Random();
System.out.println("How many questions do you want?");
[code]...
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Feb 26, 2015
I've been writing classes over and over for school. So I create a class outside of my main class. I create a new constructor and then create objects from my main class. I hope that makes sense. So i use methods in that class to work with the object. So I have an object name I've created <dot> method name. So I can create objects and then use methods from the class, but I'm wondering can I create a method in my main class and use it on that object? I don't understand how to do that.
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Jun 9, 2014
im trying to create an insertion sort method for a vector. I know how to insertionsort for an array, but for a vector im having problems
Source code:
PHP Code: package test;
import java.util.*;
import java.io.*;
public class LinearSearch {
public static void main (String[] args) {
Vector myVector = new Vector();
[Code]...
I'm getting errors at lines 38 and 39 "Left-hand side of an assignment must be a variable". "Syntax-error(s) on token(s) misplaces contructor(s)". How can i fix them ??
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Apr 16, 2015
I need figuring this problem out. It appears that I am attempting to generate a permutation of the string "ABCDEF" 720,000 times using this method:
In the second method, j is chosen randomly in the range from 0 to i (inclusive).
Once the permutations are generated, the program will proceed in counting the number of times each permutation occurs, calculating the chi square statistic of the situation, and creating the chi square distribution with 719 degrees of freedom, then outputting the statistic and the chi square probability of the permutations. The generatePermutation method is where all the magic happens. Only trouble, I can't figure out what I equals to. The times where I think I have i as a correct value only give me the program outputted as 1.0 probability every time. What it needs to be doing is outputting variable probability as a number always between 0 and 1, not 1 all the time. Here is my code:
assignment7part2.java:
package math3323assignment7;
import java.util.HashMap;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Random;
import org.apache.commons.math3.distribution.ChiSquaredDistribution;
import com.google.common.collect.Multiset;
import com.google.common.collect.TreeMultiset;
[Code] ....
i is meant to step through the index of the array, but I can't figure out what i is.
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Feb 16, 2014
I have two classes: main (with JFrame) and a panelLogin class with a method returning a panel with all login components..so I create a new panelLogin in main and use the method to get the panel, put it into my JFrame. But here the problem: on the loginPanel the ActionListener for the login-event, if the input is correct,the panel shall disappear and the main panel shall appear.Should I make some kind of top class, which handels the panels?
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Aug 9, 2014
Essentially, the code I want is:
public void randomCreate(ParentObject obj){
int x = random(0-4); //pseudo
int y = random(0-4); //pseudo
create new ParentObj(x,y);
}
ParentObject is actually abstract, so you would only ever pass one of its children objects to it, and a child object of that type would be created. It seems like there should be a way to pass a type, rather than an object, and then create an instance later down, but I don't know if that is actually possible, or if it is poor programming style.
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May 11, 2015
I am having trouble with methods. What I want to do is be able to create 4 types of strings under the same method, but only draw one of them at a time.
i.e
UI.initialise;
UI.addButton ("pipe", this::drain);
public void drain(){
this.pipe ("pipe1");
this.pipe ("pipe2");
[Code] ....
When I press the button "drain" it will print=
pipe1
pipe2
pipe3
pipe4
I am having a lot of difficulty just printing one out after each time I press drain.
"drain"
pipe1
"drain"
pipe2 etc..
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Feb 7, 2015
In my book for learning java, one of the questions asks us to create a method header named convertTOKM that takes an int parameter, which is the number of miles, and returns a double value for the converted value in kilometers. I made one, but wanted to know if I was right in any way.
Here it is:public double convertTOKM(int miles, double kilometers){
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Jun 15, 2014
I am trying to create a method that calculates the standard deviation of array. What I want to be able to do is something like this
package standardDevaitionAndMean;
public class StandardDeviationTest {
public static void main (String[] args)
{
int [] array = {12,12,12,12,12,12,12};
standardDev = array.StandardDevation();
System.out.print(standardDev);
}
}
With something like this
package standardDevaitionAndMean;
public class StandardDeviation
{double mean1;
double standDev;
public double Mean(double ... array)
{
for(int i=0; i<array.length;i++)
[Code]...
So basically I want to be able to make an array in a class and be able to calculate its standard deviation with my method in my other class. I know the code I wrote is terrible but I just wanted to show what I am trying to do. I am kind of shaky on how arrays operate
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Jan 8, 2009
Create a method called mirrorImage, which takes two integer arrays as input parameters. You may assume that the two actual parameters have the same length. Your method should return true if the arrays are the reverse of each other. Otherwise mirrorImage should return false.
Examples:
data1:{1,2,3}
data2:{3,2,1}
==> true
[code].....
I'm pointing a place outside of the array or something
runtime error (line 8, column 0): java.lang.ArrayIndexOutOfBoundsException: 10
-> array.ArrayQuestions.mirrorImage()
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Apr 29, 2014
I am trying to make a game, for some reason i have begun to get a java.lang.StackOverflowError.
I am not exactly sure how i can fix it. only removing line 14 from infopannel1 (and everything that used that class.) seems to work. im not sure what else i can do to fix it. or why its resulting in stack overflow for that matter.
I am putting in a link for the files i wrote this using bluej (several classes have no relevance, errorv2, demonstration, folderreadertest, ReadWithScanner, saveloadtest, menutest,rannum, and menutestTester. are all irrelivent to my problem.)
[URL] .....
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Dec 13, 2014
how does recursion works, I don't understand why it prints al numbers going up again?This is the code
void print2(int n){
if (n<0){
out.printf(" %d",-1);
return;
}
out.printf(" %d", n);
print2(n-1)
out.printf(" %d", n);
}
this should be the output if n is 6: 6 5 4 3 2 1 0 -1 0 1 2 3 4 5 6.
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Mar 25, 2015
How to add the sum of an array with a recursion, but I don't understand how to use recursion. I just understand that it calls back the method. I am nearly done with the code.
import java.util.Scanner;
class Question1{
public static void main(String[]args){
Scanner s = new Scanner(System.in);
int size, sum;
System.out.println("Please input how many numbers will be used");
size=s.nextInt();
[Code] .....
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Aug 6, 2014
public void myFunc(MyNode n, ArrayList<MyNode> path) {
boolean hasChildren = false;
path.add(n);
int index = path.indexOf(n);
ArrayList<MyNode> statefulPath = new ArrayList<MyNode>();
[Code] ....
I have similar code that I stepped through in a debugger. After running the code I found that it built the desired tree, in this case a root node H with left child L and right child P. I want list of lists to contain all paths from root to leaf. I expected [H, L] and [H, P]. I discovered that statefulPath is not stateful; after a recursive stack frame pops, statefulPath still contains n! But that stack frame just popped! I expected to see statefulPath be [H] in the debugger and it was [H, L]! So I later have a list [H,L,P] which I don't want. How do I make the statefulPath list I want for my algorithm?
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Mar 22, 2015
I have a question related to the code below, that I do not understand. The aim is to count all files and subdirectories in an ArrayList full of files and subdirectories. So I have to count every file and every subdirectory.
The code concerning counting files is clear to me - every time d is of the type file I have to increment n by one. However I thought that I have to do the same thing in case d is a directory, so I would have written the same code for directories.
So what does "n += ((Directory) d).countAllFiles();" mean? In my understanding the method countAllFiles() is applied again on the object Directory ( as Directory is the class that contains this method), but how is n incremented by this? I thought n should be incremented by one as we did with files.
public int countAllFiles() {
int n = 0;
for(SystemFile d : content) {
if(d instanceof File) {
n++;
[Code] ....
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Jun 5, 2014
How the recursion works. I tried to figure out writing down low, mid, high at each recursive call. But I seem to be making a mistake somehow. I don't understand where the values are returned to in
if(leftmax>rightmax){
return leftmax;}
else
return rightmax;
Here's the code:
public class Maximum{
public static int max(int[] a,int low,int high){
int mid,leftmax,rightmax;
if(low==high)
return a[low];
[Code] ....
firstly leftmax=max(a,0,4)
Then what is the next line executed?Is it rightmax=max(a,5,8).
After this is it leftmax=max(a,5,6)
rightmax=max(a,7,8)
I tried to understand what these recursion calls by writing them down.But I somehow make a mistake.
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Oct 20, 2014
I just started studying recursion and I wanted to know how to create a palindrome number going up from 1 to n then back to 1 like this: "12345...n...54321".
I've done one going downwards and then upwards like this: "n...4321234...n".
Here's my code:
Java Code: import java.util.*;
public class PalindromeTest
{
public static void downPalindrome(int n)
[Code].....
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