How To Write Inorder-method For Trees
Mar 29, 2015
I have a question related to trees in Java. The following code is given:
public class BinarySearchTree {
private Node root;
public BinarySearchTree() {
this.root = null;
}
public BinarySearchTree(Node root) {
[Code] ....
The inorder-method is the one that really imports. I have to go through a tree using the Inorder-method. I do understand how this works, however I don't understand how the code fits to the inorder process. I understand the code up to the point where it reaches the most left "root", but then I do not know how to go further. How do I reach the root above then?
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May 4, 2014
I need a method to do an inorder traversal for the following class
public class TreeNode {
/** the data stored at this node */
private String data;
/** the left child */
private TreeNode left;
[Code] ....
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Jul 13, 2014
I'm trying to build a binary tree using two arrays I'm given, one is inorder and the other is postorder and I have to construct the tree based on that. I understand the strategy I need to use- the last element of the postorder array tells me the root node, and wherever the value of that node occurs in the inorder array is where the tree is split. I can then apply this idea recursively to build the tree. For whatever reason though, I keep getting stack overflows.
Here's what I have so far:
public static class TreeNode {
char val;
TreeNode left;
TreeNode right;
TreeNode(char newVal) {
val = newVal;
[Code] .....
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May 5, 2014
In this i Write a Java program to parse a syntactically correct arithmetical expression and produce an equivalent Expression TREE. Remember, in an expression tree the terminal nodes are variables and constants, and the interior nodes are operators (such as +,-,*,/). For instance the expression: (1 + 2) * 3 can be represented by the following tree:
INPUT Expression
(1 +2)*3
POSTORDER Expression
1 2 + 3 *
TREE [root=asd.reg.Node@56ddc58]
But when I Execute the program it Shows only Prefix and postfix .But the requered output is in inorder preorder and postorder ...
import ava.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;
import javax.swing.tree.TreeNode;
[code]....
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Jul 28, 2014
I have to create a dictionary in java using search trees. I have problems with the methods put() and remove(). Working properly, ie correctly adds a new element and eliminates correctly. But I should improve a few things.
As you can see from the interface, both methods must return an element of type V, that is:
- case put(): returns the previous value associated with key (or null if the key was not associated with any value)
- case remove(): returns the value associated with the key (or null if the key was not present in the dictionary)
I do not understand how come my put method always returns null even though in reality I make him return node.getElement().
Instead, the remove() method does not know how to modify it to make sure it returns the value associated with the key. If I change the helper method return value in V (instead of Node<K, V>) method does not work anymore...
How can I then edit these two methods?
Class SearchTree:
public class SearchTree<K extends Comparable, V> implements Dictionary<K, V> {
public int size;
public Node<K, V> root;
public SearchTree() {
root = null;
size = 0;
[Code] ....
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Apr 6, 2015
We are working with LinkedBinarySearchTrees. One of specs on my assignment is to "Using a level-order traversal, create a 2-D display of your trees, using the forward and back slashes as the branch lines. The tree nodes should be spaced proportionally to show the structure of the tree neatly."
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May 19, 2014
which when user enter a number then will display how many * in a line .Produce a line: ***** But my code only show 1 * there... what wrong with it ?
import java.util.Scanner;
public class display {
public static void main(String args[]) {
int i,n = 0 ;
[Code] ...
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May 7, 2014
Write a method that prints characters using the following: public static void printChars(char ch1, char ch2, int numberPerLine). This method prints the characters between ch1 and ch2 with specific numbers per line. Characters are separated by exactly one space.Test your method with the following main method:
public static void main(String[] args)
{
printChars(‘A’,’z’,10);
printChars(‘0’,’9’,5);
}
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Oct 20, 2014
I am trying to clear all graphical objects of a certain type(all trees in particular). I have never had any issues doing so, and this method normally works well along with these variables:
Java Code:
public static ArrayList<GRect> historyT;
public static ArrayList<GOval> historyL;
public static GRect trunk;
public static GOval leave;
public void deleteTrees() {
//clears all tree trunks and leaves
[Code]...
That is this normally worked until I started added more trees to the screen after they had all been erased. What happens is that it won't clear all of them unless the max has been reached, that is 6. It will remove all trees up till the last one if the max has not been reached. In other words here is my screen before the clear all if the max has not been reached(* is a tree, _ is erased): ****
Here is it after: _ _ _ _ *
So my question is, is why aren't all the trees deleted? Why does it leave one left behind?
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Mar 15, 2014
Suppose that a certain BST has keys that are integers between 1 and 10, and we search for 5. Which sequence below cannot be the sequence of keys examined?
(a) 10,9,8,7,6,5
(b) 4,10, 8, 6, 5
(c)1,10,2,9,3,8,4,7,6,5
(d) 2,7,3,8,4,5
(e)1,2,10,4,8,5
I've noticed many differences, such as there is only one with an odd number of keys, and one has all integers from 1-10 inside of it, but I can't find any real reason that you wouldn't be able to search it?
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Apr 11, 2014
So here is a method i wrote for the first part for initializing an array:The question was, "write a method which initializes a 2D target array (assuming all other classes have been imported and given), and all targets should be stationary."and this was my method i wrote:
public void initializeTargetArray(Target[][] targets) {
int row = targets.length();
int col = targets[0].length;
for(int i = 0; i < row; i++)
for (int j = 0; j < col; j++)
targets[i][j] = new Target(Target.STATIONARY, false);
}
Now my question how do I initialize an array similar to the method above for a different question?
Quote
Part b
Write a method which initializes an array (You can assume that the 2D array itself (but not the Target
objects inside) is already initialized), where the game level stage is now set:
Game level 1 - all targets are stationary,
Game level 2 - For even numbered rows, targets at even numbered columns are stationary, targets at odd
numbered columns are movable. For odd numbered rows, targets at odd numbered columns are
stationary, targets at even numbered columns are movable.
Game Level 3 - All targets are movable.
public void initializeTargetArray(Target[][] targets, int gameLevel) {
//*** Finish this method. ***//
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May 6, 2014
I Write a Java program to parse a syntactically correct arithmetical expression and produce an equivalent Expression TREE. Remember, in an expression tree the terminal nodes are variables and constants, and the interior nodes are operators (such as +,-,*,/).
For instance the expression: (1 + 2) * 3 can be represented by the following tree:
INPUT Expression
(1 +2)*3
POSTORDER Expression
1 2 + 3 *
TREE [root=asd.reg.Node@56ddc58]
But when i Execute the program it Shows only Prefix and postfix .But the requered output is in inorder preorder and postorder so how to solve these error
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;
import javax.swing.tree.TreeNode;
public class InToPost {
private static String str;
[Code] .....
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Nov 8, 2014
I am a student taking a Java programming class. My assignment is to write a program that converts a roman numeral input as entered by a user and converting it to it's integer value (arabic number). These are the methods that I must have in it:
1. Write a method that takes input from the user and passes it to a conversion method.
2. Write a method that yields the numeric value of each of the letters (conversion method).
3. Write a method that outputs the number the user entered and the converted number.
4. Write a main method to test the 3 methods.
I have written the first method, at least I think. Here is what I did there:
public static String romanInput(String number) {
Scanner numberInput = new Scanner (System.in);
System.out.print("Enter a roman numeral: ");
String userInput = numberInput.next();
return userInput;
}
I returned the userInput and I think that is passing it to the conversion method? Now I am working on this conversion method and to be honest I don't know where to begin. I am told how to convert a string in my assignment by the professor. I am told:
- Look at the first two characters. If the first has a larger value than the second, then simply convert the first.
- Call the conversion method again for the substring starting with the second character.
-Add both values. If the first one has a smaller value than the second, compute the difference and add to it the conversion of the tail.
I am also told to use a single-dimensional array. But, I don't know what I am to use a single dimensional array for? So this is what I wrote so far for this method:
public static int numberConversion(int number) {
int romanConv = 0;
char[] romanNum = {'I', 'V', 'X', 'L', 'C', 'D', 'M'};
char[] arabicNum = {1, 5, 10, 50, 100, 500, 1000};
romanNum = arabicNum;
}
I have written a character array for the roman numerals, and then one for arabic numerals, then I set them equal to each other. I also declared an integer variable set to 0 because I think that is what I will be returning at the end of the method. Now I don't know where to start for the conversion algorithm here. I know this is what I have to do, but I don't know how to do it:
1. Add the numbers together if they are in decreasing value or are equal in value. For example: VI is read as 5 + 1 = 6 XVI is read as 10 + 5 + 1 = 16 XXXVIII is 10 + 10 + 10 + 5 + 1 + 1 + 1 = 38
2. Use subtraction if a number is less than the number that follows it. For example, I is less than V, so when I is in front of V, you subtract its value.
3. For example: IV is 5 1 = 4 IX is 10 1 = 9 XL is 50 10 = 40 MCM is 1,000 + (1,000 - 100) = 1,900
I can't use hashtables or enums because I haven't learned about that yet. I have a feeling I need to use a for loop. I know I haven't done any of the actual programming work but I don't know how to begin writing this conversion method.
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Oct 25, 2014
I must write a method that accepts a string and returns an int. The method should sum the unicode values of each character, so the string "ABC" should return 198. Also the only string class methods I'm aloud to use are length, charAt, and substring. I just don't know how the get the Unicode value.
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May 29, 2014
Write an instance method, contains, that has one explicit parameter of type Rectangle. The method should return true if every point of the rectangle determined by the explicit parameter is on or within the rectangle determined by the implicit parameter. It should return false otherwise.
This is what i did so far?
public boolean contains(Rectangle other) {
Rectangle intersect = Rectangle.intersection(this, other);
if ((intersect.left == this.left) && (intersect.bottom == this.bottom) && (intersect.width == this.width)
&& (intersect.height == this.height)) {
return true;
} else {
return false;
}
}
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Mar 23, 2015
How do i write a method in java that will add a <b> or <em> tag to a specific word regardless of case or punctuation for example for "run forest RUN!" adding bold to run would be
<b>run<b> & <b>RUN!<b>
public void addTag(String word, String tag) {
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Dec 3, 2014
I have understood my programming class up to this point and now I have been given a lab that I can't figure out for the life of me. Here what I have to do: Write a program that will call a method (called f) to calculate the following function" f(x)=(x^2)-16...this is what the output should be:
x f(x)
1 -15
2 -12
3 -7
4 0
5 9
6 20
7 33
8 48
9 65
10 84
I guess it also has to print this output in a table even though my professor never mentioned it. Usually
public class Lab12 {
public static int f(int x)
{
return x*x-16;
[code]....
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Jan 26, 2014
Any link to the accurate explanation of binary trees in java?
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Apr 22, 2015
I am supposed to write a static method that simulates a flip of a weighted coin by returning either heads or tails each time it is called. The coin is twice as likely to turn up heads as tails. My idea was to of course use a random class
Random flip = new random
and somehow initialize it so 3 numbers are called and create if statements so that when 0 and 1 are called heads returns and when 3 is called tails is.How do I put all this together?
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Sep 1, 2014
I wrote this program to prompt user to enter his choice to do a i/o operation in a file. It shows error. How to clear the error. My code is:
import java.io.*;
import java.util.*;
class Files {
public static void main(String args[]) {
String n;
[Code] ....
error:
E:java>javac Files.java
Files.java:26: error: no suitable method found for write(String)
fos.write(n);
[Code] ....
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Oct 27, 2014
So I am calling this method several times and trying to write multiple records to a file. Problem is that every time I call the method it overwrites the file from before and doesn't add it.
public void fileWriterMethod() throws IOException{
RandomAccessFile raf = new RandomAccessFile(filename, "rw");
raf.writeInt(id);
raf.writeInt(existingMileage);
raf.writeInt(gasCost);
raf.writeInt(ndays);
raf.writeInt(rate);
raf.writeInt(totalCharge);
raf.writeInt(discount);
raf.writeInt(tax);
raf.writeInt(netCharge);
raf.writeInt(returnMileage);
raf.writeBytes(carName + "
");
//Closing the stream
raf.close();
}
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Apr 22, 2014
i have to "Write a method called addToOverThirty which takes the array nums3 as a parameter. It adds 1 to all numbers that have a value greater than 30 in the array.
Add a call to the addToOverThirty method, then display a message telling what the output is followed by the results For example:The nums3 array after adding 1 to all numbers greater than 30 is10 6 15 and so on (check with the values you assigned to nums3)"its pointless because we were told not to make the array have a number over 30.
import java.lang.*;
import java.util.*;
public class LastProject
public static void main(String[] args) {
int nums1[] = new int[15];
int nums2[] = new int[15];
int nums3[] = {5,2,15,8,26,22,1,29,4,23,30,11,19,6,24};
[code]....
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Feb 20, 2014
In a forest, there are some bamboo trees .The length of each tree get doubled during winter and increases by one unit in summer , write a Java program to calculate the total length of n number of bamboo trees in M number of seasons. The season always starts with winter.
import java.util.Scanner;
public class Tree {
public static void main(String args[]) {
int length;
int season;
[Code] ....
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May 27, 2014
I'd like to know how to return a new array, I wrote in a method below the main method. I want to print the array but system.out.print doesn't work for arrays apparently. What structure i should use?
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May 27, 2014
I have to write a method called censor that gets an array of strings from the user as an argument and then returns an array of strings that contains all of the original strings in the same order except those with length of 4. For example if cat, dog, moose, lazy, with was entered, then it would return the exact same thing except for the words with and lazy.
Currently, my code so far just prints [Ljava.lang.String;@38cfdf and im stuck.
import java.util.Scanner;
public class censorProgram {
public static void main (String args[]){
Scanner input = new Scanner (System.in);
System.out.println ("How many words would you like to enter?");
int lineOfText = input.nextInt();
[Code] ....
I have to make new string array in the method and return words without four letters in the main method
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Apr 29, 2014
Consider the following recursive method that calculates the greatest common divisor using Euclidean method.
PHP Code:
public static int GCD ( int x , int y )
{
if ( y == 0 )
return x;
else if ( x >= y && y > 0)
return GCD ( y , x % y );
else return GCD ( y , x );
}
Trace the above method for x=32 and y=46
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