CC-20 : Implement a basic HashSet implementation POC.

Description:

Implement a basic HashSet POC. Implement methods such as hash(), add(), remove(), contains() which demonstrate HashSet functionalities.

Test cases and expected outputs:

Input Parameters	Expected outputs
DHashset sp=new DHashset(); sp.add(700); sp.add(250);
sp.contains(700);	true
sp.remove(250);
sp.contains(250);	false

Pseudocode:

Create a java class called DHashSet.

In DHashSet initialize an int member variable named capacity and set it to 10000.

In DHashSet initialize a member variable boolean array named set with size equal to capacity. Note by default all indexes of set are set to false indicating our HashSet is empty.

Create a method hash() that takes a key as input:

Return basic hash calculated by key%capacity.

Create a method add() that takes a key as input:

Set hashkey=hash(key).

Set set[hashkey] to true.

Now set[hashkey] being true means we have stored key in set.

Create a method remove() that takes a key as input:

o Set hashkey=hash(key).

o Set set[hashkey] to false.

o Now set[hashkey] being false means key is now no longer stored in set.

Create a method contains() that takes a key as input:

Set hashkey=hash(key).

if set[hashkey] is true, it means key is stored in hash. If set[hashkey] is false, it means key is not stored in hash. Return set[hashkey].

Code:

public class DHashset {

private int capacity=10000;
private boolean[] set= new boolean[capacity];


public int hash(int key) {
	return key%capacity;
}

public void add(int key) {
	int hashkey=hash(key);
	set[hashkey]=true;
}

public void remove(int key) {
	int hashkey=hash(key);
	set[hashkey]=false;
}


public boolean contains(int key) {
	int hashkey=hash(key);
	return set[hashkey];
}
}

Click here to download and run code and test cases !

Below fully running code can be copied and run on Eclipse or other Java IDEs. Refer the classname in code below. If the class name below is "A", save the code below to a file named A.java before running it. Be sure to try your own test cases to enhance your understanding ! You can also tweak the code to optimize or add enhancements and custom features.

public class DHashset {

private int capacity=10000;
private boolean[] set= new boolean[capacity];


public int hash(int key) {
	return key%capacity;
}

public void add(int key) {
	int hashkey=hash(key);
	set[hashkey]=true;
}

public void remove(int key) {
	int hashkey=hash(key);
	set[hashkey]=false;
}


public boolean contains(int key) {
	int hashkey=hash(key);
	return set[hashkey];
}


	
public static void main(String[] args) {
		
	DHashset sp=new DHashset();
	try {
	sp.add(700);
	sp.add(250);
	System.out.println("700" + sp.contains(700));
	System.out.println("250" + sp.contains(250));
	sp.remove(250);
	System.out.println("250 after removed" +sp.contains(250));
	sp.add(15000);
	System.out.println("15000" + sp.contains(15000));
	sp.remove(15000);
	System.out.println("15000 after removed"+sp.contains(15000));
			
			
	}catch (Exception exception) {
	System.out.print("Exception,"+ exception);
	exception.printStackTrace();
				
	}
}
			

}