// Adds a key value pair to hash
public void add(K key, V value)
{
// Find head of chain for given key
int bucketIndex = getBucketIndex(key);
HashNode <K, V> head = bucketArray[bucketIndex];
// Check if key is already present
while (head != null)
{
if (head.key.Equals(key))
{
head.value = value;
return;
}
head = head.next;
}
// Insert key in chain
size++;
head = bucketArray[bucketIndex];
HashNode <K, V> newNode = new HashNode <K, V>(key, value);
newNode.next = head;
bucketArray[bucketIndex] = newNode;
// If load factor goes beyond threshold, then
// double hash table size
if ((1.0 * size) / numBuckets >= 0.7)
{
var temp = bucketArray;
bucketArray = new List <HashNode <K, V> >();
numBuckets = 2 * numBuckets;
size = 0;
for (int i = 0; i < numBuckets; i++)
{
bucketArray.Add(null);
}
foreach (HashNode <K, V> x in temp)
{
var headNode = x;
while (headNode != null)
{
add(headNode.key, headNode.value);
headNode = headNode.next;
}
}
}
}
// Method to remove a given key
public V remove(K key)
{
// Apply hash function to find index for given key
int bucketIndex = getBucketIndex(key);
// Get head of chain
HashNode <K, V> head = bucketArray[bucketIndex];
// Search for key in its chain
HashNode <K, V> prev = null;
while (head != null)
{
// If Key found
if (head.key.Equals(key))
{
break;
}
// Else keep moving in chain
prev = head;
head = head.next;
}
// If key was not there
if (head == null)
{
return(default(V));
}
// Reduce size
size--;
// Remove key
if (prev != null)
{
prev.next = head.next;
}
else
{
bucketArray[bucketIndex] = head.next;
}
return(head.value);
}
// Returns value for a key
public V get(K key)
{
// Find head of chain for given key
int bucketIndex = getBucketIndex(key);
HashNode <K, V> head = bucketArray[bucketIndex];
// Search key in chain
while (head != null)
{
if (head.key.Equals(key))
{
return(head.value);
}
head = head.next;
}
// If key not found
return(default(V));
}
