Hash tables, hash maps, and similar data structures allow indexing by a unique key, but that indexing is implemented in a very specific way. Hash tables essentially use an array, but that array is indexed by a hash value. Associative arrays are not supported by Java, however, using a Map, this could easily be resolved. C++ has std::unordered_map.<\/p>\n
The idea with hashing is to convert a complex input value into a different value that can be used to extract or store data faster. Chain hashing collisions are avoided. The hash function is the value to link each cell of the hash table to a list of records.<\/p>\n
Linear checking technique:- In this technique, each cell in a hash table has a single key-value pair. If a collision occurs by mapping a new key into the cell of the hash table, which is already occupied by another key. This method searches the table for the following nearest free space and inserts the new key there.<\/p>\n
Examples:<\/strong><\/p>\n Inserting a key:- Delete:-C++:<\/h3>\n
\n
\nBegin
\n Insert(int a, int b)
\n \tint hashVal = HashFunc(a)
\n \tinit = -1
\n \tdeleteIndex = -1
\n \twhile (hashVal != init and (ht[hashVal]==delNode::getNode() or ht[hashVal]!= NULL and ht[hashVal]->a != a))
\n \tif (init == -1)
\n \tinit = hashVal
\n \tif (ht[hashVal] == delNode::getNode())
\n \tdeleteIndex = hashVal
\n \thashVal = HashFunc(hashVal + 1)
\n \tif (ht[hashVal] == NULL || hashVal == init)
\n \tif(deleteIndex != -1)
\n \tht[deleteIndex] = new HashTable(a, b)
\n \telse
\n \tht[hashVal] = new HashTable(a, b)
\n \tif(init != hashVal)
\n \tif (ht[hashVal] != delNode::getNode())
\n \tif (ht[hashVal] != NULL)
\n \tif (ht[hashVal]->a== a)
\n \tht[hashVal]->b = b
\n \telse
\n \tht[hashVal] = new HashTable(a, b)
\nEnd<\/p>\n
\nBegin
\n Remove(int a)
\n \tint hashVal = HashFunc(a)
\n \tinit = -1
\n \twhile (hashVal != init and (ht[hashVal] == delNode::getNode() or ht[hashVal]!= NULL and ht[hashVal]->a!= a))
\n \tif (init == -1)
\n \tinit = hashVal
\n \thashVal = HashFunc(hashVal + 1)
\n \tif (hashVal != init && ht[hashVal] != NULL)
\n \tdelete ht[hashVal]\n \tht[hashVal] = delNode::getNode()
\nEnd
\n<\/code><\/p>\nJava:<\/h3>\n