Question

write the code in java please

Write code for an [add remove contains |rehash getLoad] method in a hash table which uses [separate chaining | open addressing with linear probing open addressing with quadratic probing | open addressing with double hashing where h2(key)-7-(key % 7)].

Answer 1

Answer:

Java Code:

public void add(K key, V value) {

int index = getBucketIndex(key);

MapNode<K, V> head = buckets.get(index);

while(head != null) {

if(head.key.equals(key)) {

head.value = value;

return;

}

head = head.next;

}

MapNode<K, V> newNode = new MapNode<K, V>(key, value);

newNode.next = buckets.get(index);

buckets.set(index, newNode);

size++;

double loadFactor = (size * 1.0) / buckets.size();

if(loadFactor > 0.7) {

rehash();

}

}

private void rehash() {

System.out.println("Rehash");

ArrayList<MapNode<K, V>> temp = buckets;

buckets = new ArrayList<MapNode<K,V>>();

for(int i = 0; i < 2*temp.size()+1; i++) {

buckets.add(null);

}

size = 0;

for(int i = 0; i < temp.size(); i++) {

MapNode<K, V> head = temp.get(i);

while(head != null) {

insert(head.key, head.value);

head = head.next;

}

}

}

public void remove(K key) {

int index = getBucketIndex(key);

MapNode<K, V> head = buckets.get(index);

MapNode<K, V> prev = null;

while(head != null) {

if(head.key.equals(key)) {

if(prev == null) {

head = head.next;

buckets.set(index, head);

}

else {

prev.next = head.next;

}

size--;

return;

}

prev = head;

head = head.next;

}

}

public V contains(K key) {

int index = getBucketIndex(key);

MapNode<K, V> head = buckets.get(index);

while(head != null) {

if(head.key.equals(key)) {

return head.value;

}

head = head.next;

}

return null;

}