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In this article, we will learn what is hashing in data structure, index mapping in hashing, what is a collision in a hash table in data structure, separate chaining collision handling technique in hashing, and open addressing collision handling technique in hashing.<\/p>\n
It is a method for storing and retrieving data from a database in O(1) time. Sometimes it is called mapping. With the help of hashing in data structure, we convert larger values into smaller values using the concept of hashing.
\nWith the help of the search key, we point the data into the database and for this, we use a pointer in hashing.<\/p>\n
There are three main terms in hashing.<\/p>\n
1. Search Key<\/strong> 2. Hash Table in data structure<\/strong> 3. Hash Function<\/strong> There are mainly one hash function methods.<\/p>\n We will understand the above terminology with the help of the example and we will also learn index mapping in a hash table in the data structure.<\/p>\n Here, we use the hash function ( k mod 10) to put the search key in a hash table. That is why in a hash table we have a 0-9 index number.<\/p>\n Example:<\/strong><\/p>\n Search key ( 45, 56. 17, 23, 32, 81) For key: 45 For key: 56 Likewise, We will calculate the hash value for left keys and put the key in a hash table according to its hash value.<\/p>\n After inserting a key in a hash table in data structure, hash table looks like:<\/p>\n Code Implementation<\/strong>
\nIt is a unique number that we will put into a hash table to retrieve or store data from a database.
\nFor example, We find out a particular student in a classroom with the help of the student roll number.<\/p>\n
\nIt is a data structure that provides a methodology to store data in a proper way. It looks like an array but in actuality, it is not an array.<\/p>\n
\nUsing the hash function, we insert, delete and search data in a hash table in O(1) time. <\/p>\n\n
\nIn this function, we divide the search key by N and get a reminder. The reminder is a hash value. A hash value is the index number of the hash table and we will put the search key on that index number in a hash table.<\/li>\n<\/ul>\nIndex Mapping in Hashing<\/h2>\n
\nHash function ( k mod 10)<\/p>\n
\nHash Value: 45 mod 10 = 5
\nSo we will map 45 at index number 5 of a hash table.<\/p>\n
\nHash Value: 56 mod 10 = 6
\nSo we will map 56 at index number 6 of a hash table.<\/p>\n\n\n
\n \nSearch Key<\/th>\n Index<\/th>\n<\/tr>\n<\/thead>\n \n <\/td>\n 0<\/td>\n<\/tr>\n \n 81<\/td>\n 1<\/td>\n<\/tr>\n \n 32<\/td>\n 2<\/td>\n<\/tr>\n \n 23<\/td>\n 3<\/td>\n<\/tr>\n \n <\/td>\n 4<\/td>\n<\/tr>\n \n 45<\/td>\n 5<\/td>\n<\/tr>\n \n 56<\/td>\n 6<\/td>\n<\/tr>\n \n 17<\/td>\n 7<\/td>\n<\/tr>\n \n <\/td>\n 8<\/td>\n<\/tr>\n \n <\/td>\n 9<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
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