Code:
import java.util.Scanner;
/** Class QuadraticProbingHashTable **/
class QuadraticProbingHashTable
{
private int currentSize, maxSize;
private String[] keys;
private String[] vals;
/** Constructor **/
public QuadraticProbingHashTable(int capacity)
{
currentSize = 0;
maxSize = capacity;
keys = new String[maxSize];
vals = new String[maxSize];
}
/** Function to clear hash table **/
public void makeEmpty()
{
currentSize = 0;
keys = new String[maxSize];
vals = new String[maxSize];
}
/** Function to get size of hash table **/
public int getSize()
{
return currentSize;
}
/** Function to check if hash table is full **/
public boolean isFull()
{
return currentSize == maxSize;
}
/** Function to check if hash table is empty **/
public boolean isEmpty()
{
return getSize() == 0;
}
/** Fucntion to check if hash table contains a key **/
public boolean contains(String key)
{
return get(key) != null;
}
/** Functiont to get hash code of a given key **/
private int hash(String key)
{
return key.hashCode() % maxSize;
}
/** Function to insert key-value pair **/
public void insert(String key, String val)
{
int tmp = hash(key);
int i = tmp, h = 1;
do
{
if (keys[i] == null)
{
keys[i] = key;
vals[i] = val;
currentSize++;
return;
}
if (keys[i].equals(key))
{
vals[i] = val;
return;
}
i = (i + h * h++) % maxSize;
} while (i != tmp);
}
/** Function to get value for a given key **/
public String get(String key)
{
int i = hash(key), h = 1;
while (keys[i] != null)
{
if (keys[i].equals(key))
return vals[i];
i = (i + h * h++) % maxSize;
System.out.println("i "+ i);
}
return null;
}
/** Function to remove key and its value **/
public void remove(String key)
{
if (!contains(key))
return;
/** find position key and delete **/
int i = hash(key), h = 1;
while (!key.equals(keys[i]))
i = (i + h * h++) % maxSize;
keys[i] = vals[i] = null;
/** rehash all keys **/
for (i = (i + h * h++) % maxSize; keys[i] != null; i = (i + h * h++) % maxSize)
{
String tmp1 = keys[i], tmp2 = vals[i];
keys[i] = vals[i] = null;
currentSize--;
insert(tmp1, tmp2);
}
currentSize--;
}
/** Function to print HashTable **/
public void printHashTable()
{
System.out.println("\nHash Table: ");
for (int i = 0; i < maxSize; i++)
if (keys[i] != null)
System.out.println(keys[i] +" "+ vals[i]);
System.out.println();
}
}
/** Class QuadraticProbingHashTableTest **/
public class QuadraticProbingHashTableTest
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
System.out.println("Hash Table Test\n\n");
System.out.println("Enter size");
/** maxSizeake object of QuadraticProbingHashTable **/
QuadraticProbingHashTable qpht = new QuadraticProbingHashTable(scan.nextInt() );
char ch;
/** Perform QuadraticProbingHashTable operations **/
do
{
System.out.println("\nHash Table Operations\n");
System.out.println("1. insert ");
System.out.println("2. remove");
System.out.println("3. get");
System.out.println("4. clear");
System.out.println("5. size");
int choice = scan.nextInt();
switch (choice)
{
case 1 :
System.out.println("Enter key and value");
qpht.insert(scan.next(), scan.next() );
break;
case 2 :
System.out.println("Enter key");
qpht.remove( scan.next() );
break;
case 3 :
System.out.println("Enter key");
System.out.println("Value = "+ qpht.get( scan.next() ));
break;
case 4 :
qpht.makeEmpty();
System.out.println("Hash Table Cleared\n");
break;
case 5 :
System.out.println("Size = "+ qpht.getSize() );
break;
default :
System.out.println("Wrong Entry \n ");
break;
}
/** Display hash table **/
qpht.printHashTable();
System.out.println("\nDo you want to continue (Type y or n) \n");
ch = scan.next().charAt(0);
} while (ch == 'Y'|| ch == 'y');
}
}
Output:
Hash Table Test
Enter size
5
Hash Table Operations
1. insert
2. remove
3. get
4. clear
5. size
1
Enter key and value
N nitrogen y 1 O oxygen y 1 C carbon y 1 Cl chlorine y 1 Zn zinc
Hash Table:
N nitrogen
Do you want to continue (Type y or n)
Hash Table Operations
1. insert
2. remove
3. get
4. clear
5. size
Enter key and value
Hash Table:
N nitrogen
O oxygen
Do you want to continue (Type y or n)
Hash Table Operations
1. insert
2. remove
3. get
4. clear
5. size
Enter key and value
Hash Table:
C carbon
N nitrogen
O oxygen
Do you want to continue (Type y or n)
Hash Table Operations
1. insert
2. remove
3. get
4. clear
5. size
Enter key and value
Hash Table:
Cl chlorine
C carbon
N nitrogen
O oxygen
Do you want to continue (Type y or n)
Hash Table Operations
1. insert
2. remove
3. get
4. clear
5. size
Enter key and value
Hash Table:
Cl chlorine
Zn zinc
C carbon
N nitrogen
O oxygen
Do you want to continue (Type y or n)
y
Hash Table Operations
1. insert
2. remove
3. get
4. clear
5. size
2
Enter key
Zn
i 1
Hash Table:
Cl chlorine
C carbon
N nitrogen
O oxygen
Do you want to continue (Type y or n)
y
Hash Table Operations
1. insert
2. remove
3. get
4. clear
5. size
1
Enter key and value
Cl
chloro
Hash Table:
Cl chloro
C carbon
N nitrogen
O oxygen
Do you want to continue (Type y or n)
y
Hash Table Operations
1. insert
2. remove
3. get
4. clear
5. size
2
Enter key
Cl
Hash Table:
C carbon
N nitrogen
O oxygen
Do you want to continue (Type y or n)
y
Hash Table Operations
1. insert
2. remove
3. get
4. clear
5. size
5
Size = 3
Hash Table:
C carbon
N nitrogen
O oxygen
Do you want to continue (Type y or n)
y
Hash Table Operations
1. insert
2. remove
3. get
4. clear
5. size
4
Hash Table Cleared
Hash Table:
Do you want to continue (Type y or n)
y
Hash Table Operations
1. insert
2. remove
3. get
4. clear
5. size
5
Size = 0
Hash Table:
Do you want to continue (Type y or n)
n
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