Linear Search Of Arraylist By Last Name
Nov 5, 2014
I am having some trouble with linear search of a customers last name. I can't seem to get it to work. I have looked up examples but cant find many with Array Lists. Here is my code.
import java.util.ArrayList;
import java.util.Scanner;
public class AccountDriver {
public static void main(String[] args) {
ArrayList<Account> al = new ArrayList<Account>();
ArrayList<Customer> cust = new ArrayList<Customer>();
Scanner scan = new Scanner(System.in);
[code]....
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Apr 5, 2014
I am attempting to find the element that holds the lowest time ( i have used System.currentMillisTime ) in the array using a linear search and to then print the times held by the array in lowest to highest order . While i understand how to do a linear search using user input as the key i am not to sure how to do it by initializing a search key in the program to the lowest number and have little experience in using a search in a program that is not a simply linear search. i have attempted to code this, as seen below, but i know i am definitely wrong and i have tried another of different ways even Array.sort and then a binary search .
static long store_MAX[]; // Now an ‘array’ of ints
static int deptSize; // Holds the length of the buffer
private int shopper_MAX; // Holds the number of items in the buffer
[Code].....
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Jun 8, 2014
im trying to make a linear search method to check if a number 'n' is included in an array.
PHP Code:
package test;
public class Recursion {
public static void main(String[] args) {
}
static int linearSearch(int n, int[] array)
[code]....
Im getting the following error: this method must have a result type of type int ?? i already have a return type of type int...
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Jan 26, 2015
I try to create a jsf project within ejb which is add new car with entering attributes listing attributes and search by make.
Add and list methods working well , but have problem of list method. I tryed many combinations (using enhanced loop, iterative loop) but i cant provide working well. Always outputText returns nothing ,when i enter attributes.
Here is ejb code for adding ,getting and listing car items :
@Stateful
public class CarsBusiness implements CarsBusinessLocal {
List<Car> cars;
public CarsBusiness() {
cars = new ArrayList<Car>();
[Code] .....
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Aug 18, 2014
I have done this before in C++ but now I want to do it in Java. I am not sure how to iterate through a ArrayList, I have look several places because lets be honest the first stop is normally google. I tried the examples but with no luck.
for(auto it= foo.begin(); it!= foo.end(); foo++) {
*it //do something.
}
Here is the program:
package org.search.BFS;
import java.util.Queue;
public class BFS extends Graph {
private Queue<Integer> q;
BFS(int s) {
//mark all the vertices as not visited.
Also the below is giving me a Type safety: The expression of type ArrayList[] needs unchecked conversation to conform to ArrayList<Integer>[]
adj = new ArrayList[V];
What does this mean?
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Oct 14, 2014
I am very new to coding and I am struggling with one of my intro to Java Projects. This project involves creating a GUI that has a list of trees and their possible heights, giving each tree a range for their possible minimum and maximum heights.
I am having trouble creating this method for the TreeDatabase (TreeDB class):
public String queryByPossibleHeight(int key) Instructions for this method are as follows: this method creates and returns a single string that contains the trees that can be found such that the value key is in the range for possible height. Traverse the entire ArrayList of Trees and for each one of the trees contained in the ArrayList invoke the method inRange() from the class Tree. Pass to the method inRange() the parameter key. If inRange() returns true, invoke the method toString() from the class Tree. Append the value returned by invoking the method toString() to the String result, adding a “” at the end. Once the entire ArrayList has been traversed, return the String result.
My 3 classes so far (I haven't gotten to the actual GUI yet):
public class Range {
private int low;
private int high;
private int value;
public Range(int plow,int phigh){
low = plow;
high = phigh;
[Code]...
As you can see in the last TreeDB class, in the public String queryByPossibleHeight(int key) method I have something wrote in, but I was just testing random things.
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Mar 30, 2014
This is the code fragment I have for searching my ArrayList. Now, each contact is stored in the ArrayList with five elements (first name, last name, etc.) and they're Strings. The error I get when I try to compile my program lies within this code fragment. It says it cannot find the symbol for the search method. I'm not quite sure what to do with this error.
int foundIndex = SAAddressBook.search(aBook);
System.out.println();
if (foundIndex > -1)
aBook.get(foundIndex).displayContact();
else {
System.out.println("No Entry Found");
}
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May 11, 2012
I'm doubted regarding the implementation of Collections.binarySearch() method on an ArrayList of objects of a custom class Movie.
Here is the movie class :
public class Movie implements Comparable<Movie> {
String movieName;
String rating;
String director;
String theme;
[Code] .....
The sort/binarySearch in searchByMovieName function is done with natural sorting (and Comparable Interface in Movie class). I mean no comparators involved here. And the comparator that I used for sorting/binarySearching on Movies Director attribute in searchByMovieDirector function is :
public class MovieDirectorComparator implements Comparator<Movie> {
public int compare(Movie movie1, Movie movie2) {
return movie1.getDirector().compareToIgnoreCase(movie2.getDirector());
}
}
But I was not able to implement binarySearch ?? How to implement the binarySearch here. I have google to see only binarySearch working on Arrays or probably ArrayList of String only, but not on ArrayList of custom objects.
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Mar 15, 2015
Design a class named LinearEquation for a 2 X 2 system of linear equations:
ax + by = e
cx + dy = f
Where
x =
ed − bf/ad − bc
y =
af − ec/ad − bc
The class contains:
- Private data fields a, b, c, d, e, and f.
- A constructor with the arguments for a, b, c, d, e, and f.
- Six get methods for a, b, c, d, e, and f.
- A method named isSolvable() that returns true if ad−bc is not 0.
- Methods getX() and getY() that return the solution for the equation.
[code].....
how to display the information I need to display. Also I am not so sure that I wrote the code properly, I do not get any errors when I compile it.
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Oct 13, 2014
I'm finding common elements in a collection of arrays. This is my code so far.
import java.util.ArrayList;
import java.util.List;
public class CommonElements //< T extends Comparable<T> >
{
Comparable[] comparable;
Comparable[] tempArr;
Comparable[] tempArr1;
Comparable[] newArray = new Comparable[tempArr.length];
int comparisonCount;
[code]....
I'm using this method to sort through my array. The method accepts a collection of arrays (of varying length and of any type) as input, the algorithm input should be no greater than n(k-1). I know I can solve it using a quadratic algorithm, but it won't meet the requirement of the assignment. I did have an idea of storing all my algorithm in one giant array. After storing as one giant array I was going to sort it. After sorting I was going to compare each array side by side and see if they are the same. Here is note my teacher provided.
Note About Testing You will need to develop several sets of test collections for testing your algorithm. The grading rubric mentions covering the case where all the test collections have the same length, as well as covering the case where the test collections are of different lengths. You will also need to think about what constitutes the worst case scenario for this algorithm, since only that scenario will make your analysis of total comparisons performed a meaningful one. You can use the formulas in the grading rubric to tell you how many comparisons you should expect in the quadratic and linear cases. For example, if you have 5 total collections (1 query collection and 4 test collections), each of which contains 10 elements, the total number of comparisons performed in the worst case should be: (k - 1)N2, which for k = 10 and N = 10 is: (5 - 1)102, or 400 comparisons. For the linear algorithm, you should only have N*(k - 1), which is 10*(5 - 1), or 40 comparisons.
Here is Q/A that my teacher provided:
1. Are the elements in the collections already sorted?The input collections may or may not be sorted. Don’t assume that they are sorted.
2. Can I sort the elements in the collections? Am I supposed to sort the elements in thecollections?Yes, you can sort the elements in the collections. It is not required that you do so, however..
3. If I sort the collections, should I count the element comparisons that are performed by the sorting algorithm?No. The only element comparisons you should count are the ones that are directly used to find the common elements. Ignore comparisons performed by any sorting algorithms you use.
4. How do I extract an individual collection from the Object[] collections argument of the findCommonElements method?You will need to typecast each collection as type Comparable[]. For example:Comparable[] currentCollection = (Comparable[])collections[i];
5. Why are we using a one-dimensional Object array instead of a two-dimensional array of type Comparable (e.g., Comparable[][])?In Java, arrays are treated as objects, so only a variable of type Object[] can contain arrays. A variable of type Comparable[] can only contain Comparable elements, not arrays. A variable of type Comparable[][] also can only store Comparable elements. Although it is possible to organize the elements such that all the elements at indexes [1][i], for example, are considered to comprise a collection, this is not the same as having an array that contains other arrays. The additional bookkeeping is required to keep a 2D array organized is more complex than simply performing the typecast described above.
6. Can I use other data structures besides arrays; e.g., HashMaps?No. Although it is easier from a programming perspective to use higher order data structures like HashMaps to find common elements, using these structures simply hides the details. If you were to examine the implementations of those structures, you would probably find that they use relatively inefficient algorithms such as sequential searches to find elements. Additionally, if you use library components, you have no way of counting the number of comparisons performed, since you don’t have access to the source code of those components.
7. Is this a trick question? I can’t think of any way to get below NlogN comparisons.It is not a trick question. It is possible to solve this problem using a number of comparisons proportional to (k – 1) * N.
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Sep 22, 2013
So i was assigned to write a program that would print the answer to the system of two linear equation. the form of ax+by=c and dx+ey=f..I wrote this program, but it is incorrect since I tried it out on my terminal and I keep getting incorrect values.
import java.util.Scanner;
public class Quest4 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
[code]....
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Mar 15, 2015
The question states: Design a class named LinearEquation
for a 2 x 2 system of linear equations:
ax + by = e
cx + dy = f
Where
x =
ed − bf/ad − bc
y =
af − ec/ad − bc
The class contains:
- Private data fields a, b, c, d, e, and f.
- A constructor with the arguments for a, b, c, d, e, and f.
- Six get methods for a, b, c, d, e, and f.
- A method named isSolvable() that returns true if ad−bc is not 0.
- Methods getX() and getY() that return the solution for the equation.
Write a test program that prompts the user to enter a, b, c, d, e, and f and displays the result. If ad − bc is 0, report that "The equation has no solution."
I believe that my program is correct because I am able to compile it and get no errors, however I have no clue how to display the information for x and y or display this equation has no solution if ad-bc=0.
Java Code:
import java.util.Scanner;
public class Exer911 {
public static void main(String[] args){
// Create a scanner system to hold the numbers for each variable
Scanner input = new Scanner(System.in);
// Prompt the user to enter a number for each of the variables
[Code] ....
How to get the information to display ....
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Sep 1, 2014
I'm trying to build a method that can search a binary search tree for a specific target and then return the number of probes it took to get there. It seems to me that the best way to do this would be a recursive search method and a counter that tracks the number of calls. But I'm struggling with how to implement this. Here's the code I have so far. what works/doesn't work with the method.
// Method to search the tree for a specific name and
// return the number of probes
public T search(BTNode<T> btNode) {
[Code]....
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Apr 22, 2014
I want to create a search method that returns the frequency of a word in the search method.
public class IndexTree {
private class TreeNode {
TreeNode left;
String word;
int frequency;
TreeNode right;
[Code] .....
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Jan 16, 2014
I develop a finite element code at java. I am looking for efficiency solver and fast for large, sparse , symmetric and positive define matrices .
i used in jblas but i encounter in problem when the matrix has high condition number(ill condition number) and i get error for singular matrix while in mathematica i succeed to solve that system without problems...
Any good solver and fast solver package in java can i use for solving that system?
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Feb 28, 2014
I'm trying to create my own arraylist using Collection. My program doesn't do anything. Obviously, I haven't a clue.
import java.util.Collection;
import java.util.Iterator;
public class MyArrayList<T> implements java.util.Collection<T> {
private int size = 4;
private T[] mArray;
public MyArrayList(String[] args) {
[Code] ....
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Jul 8, 2014
I have stumbled onto a problem with ArrayLists (not sure if nested ArrayList objects would be a more accurate description) ....
As simply put as I can describe it, I have an Inventory class which creates an ArrayList of a Product superclass, which has two subclasses, PerishableProduct and ItemisedProduct.
By default, the program is meant to have a starting inventory, which is why I have added them in the constructor
public class Inventory {
private List<Product> products;
public Inventory() {
addProduct(new Product("Frying pan", 15, 20));
addProduct(new PerishableProduct("Apple", 5.8, 30, 7));
addProduct(new ItemisedProduct("Cereal", 5.8, 0));
// this is where I am having problems. Wanting to add
// objects to the ItemisedProduct's ArrayList for cereal.
}
Within the ItemisedProduct subclass is yet another ArrayList which is meant to hold serial numbers.
public class ItemisedProduct extends Product {
private ArrayList<String> serialNumbers = new ArrayList();
public ItemisedProduct(String name, double price, int qty) {
super(name, price, qty)
[Code] .....
My problem is that I do not know how to populate the serialNumbers ArrayList from the Inventory class' constructor. Because technically, quantity is defined by how many serial numbers are created.
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Jul 11, 2014
I'm trying to create a booklist in java using swings but I'm facing a problem. I don't know how to add a search function to my list. I need a search box with the book names.
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May 6, 2015
I'm Trying to write a method that search for two String from node class and return the value but when i run it
Exception in thread "main" java.lang.NullPointerException
This is the code :
public Node findName(String firstName, String lastName) {
return findName(root, firstName,lastName);
}
private Node findName(Node p, String first,String last) {
if (p == null) {
[Code] .....
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Oct 21, 2014
how to put search bar in my program.i am just new to java programming so i dont really master all the codes.i dont have much time
import java.io.*;
import java.util.Scanner;
public class myjavProject{
public static void main(String[] args)throws IOException{
PrintWriter output = null;
String ID;
String firstname;
String lastname;
String ans = "y";
String userinput;
[code]....
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Apr 3, 2015
Knowing that a hashmap does not sort the keys, I am thinking of using/converting to treemap which by nature does sort out the keys. I now need to find out if it is possible to search a treemap using partial keys such that for example I would like to search for all entries that have a key starting with "78BOX" whilst the available keys are:
75SQUARE3
76DIAMOND2
78BOX26
78BOX99
78BOX300
79TRIANGLE4
The above list is probably how treemap would sort out the keys however need to extract only those keys that start with "78BOX" - does treemap has this functionality ?
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Jun 29, 2014
// 1 ***** student writes this method
/** Searches for key in integer array named arr
// arr is an instance variable of the class and has been instantiated and filled with random values.
// @param key value to search for
// @return if key is found, the index of the first element
// in array whose value is key; if key is not found,
// the method returns -1
*/
public int sequentialSearch( int key ) {
// Note: To animate the algorithm, put this method call as the first statement in your for loop
// animate( i, 0 );
// where i is the index of the current array element
return 0; // replace this statement with your return statement
} // end of sequentialSearch
[Code] ....
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May 26, 2015
I have problem in searching for the words from my text file.. im using binary search technique
private boolean doSearchQuery(String searchQuery) throws IOException {
Log.i(TAG, "in doSearchQuery, query string: " + searchQuery);
boolean result = false;
toSort = new ArrayList<String>();
myTv = (TextView) findViewById(R.id.myFile);
[Code] .....
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Dec 14, 2014
Okay, so the assignment was creating a word search for the given array. I've created all the code necessary, but I've ran into trouble. This problem occurs with the Up-Forward, Up-Backward, Down-Forward, and Down-Backward sections. If I only set one of these to run, it works. But if I have all 4 set at the same time, it errors out on the first one that runs.
public class P_WordSearch {
public static void main(String[] args) {
char[][] puzzle = {
{'B','O','O','G','S','R','O','W','I','N','G'},
{'E','B','L','G','N','I','M','M','I','W','S'},
{'L','C','E','A','T','I','P','U','P','I','S'},
{'C','M','I','N','C','A','X','Y','O','S','N'},
[Code] ....
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Apr 15, 2014
We have this piece of code and we must make a search for a key. if the key exist it returns true if not false. Plus we must insert a key in the class. If it is already in there we say hey its already in and we don t put it again...
package askisi2;
import java.util.*;
public class mtree {
protected class tnode {
public int k1;
public int k2;
public int k3;
[Code] ....
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Jan 14, 2015
I am pretty new to Java and I am working on a sample Search code from my textbook. I can't figure out why I am getting the following error because I copied the sample exactly as it is in the book. The error is illegal start of expression on the second to last line.
public class Search {
public static final int NOT_FOUND = -1;
public static int binarySearch( int [] a, int x )
{
int low = 0;
int high = a.length - 1;
int mid;
[code]....
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