Final Summary

Linked list is a process or a way that enables us to easily edit an array  without using looping (e.g for) to count from zero to the point where we want to edit the data (also shifting is needed when editing an array).  So far, we have learned about two types of linked list. Doubly and single linked list, the first one is the circular single linked list. In circular single linked list, the last node contains a pointer to the first node which can help determine whether the data is located in the middle or in the end and also there is no storing of NULL value in the list. Secondly there is double linked list, which is a two way linked list that points to the nest data while also pointing to the previous data. Thirdly there is circular doubly linked list which is very similar to the single linked list but differ on the amount of pointer in each node (2). Just as I stated above, linked list gives us the ability to edit an array far more efficient rather than using a looping process. The reason to this is because there are processes within the linked list that enables us to do so such as Inserting and deleting certain values.

Stack is one of the basic flow of data that can come from an array list or a linked list. Imagine if there was a stack of boxes or plate. The last box or plate will be the first one to be used (LiFo: Last in First out). Just like that analogy, the "Stack" concept have only one place where the data can enter and exit which is the top. We also learned about Infix, Prefix and Postfix which is the shifting of the operators in a certain expression notation.

Hashing

Hashing is a technique used for storing and retrieving keys in a rapid manner. The string of characters is made shorter in length value but still represents its original string.

Hash Table

Hash table is a table of array where a string is stored and can be hashed. Its size is usually smaller that the total number of possible string, so several string might have a same hashed-key.

Hash Function

There are a lot of ways to hash a string into a key, the most common is Division.

Division

Division is one of the methods used to hash a string into a key, which is done by dividing the string/identifier by using the modulus operator and the value that is usually used is a prime number, the table size or the size of memory used.

“HIKE” would be stored at the location

                        ( 64+8 + 64+9 + 64+11 + 64+5) % 97 = 2

Binary Tree

Binary tree is rooted tree data structure in which each node has at most two children and the two children usually distinguish themselves as left child and right child. The node that doesn’t have any child is called leaf.

Types of binary tree

-        Perfect Binary Tree

            It is a binary tree which every level are at the same depth

-        Complete Binary Tree

            It is a binary tree in which every level except the last is completely filled and all nodes are as              far left as possible. A perfect binary tree is a complete binary tree

-        Skewed Binary Tree

            It is a binary tree in which each node has at most one child

-        Balanced Binary Tree

            It is a binary tree in which no leaf is much farther away from the root than any other leaf.

The Research

A hash is a function that converts an input of letters and numbers into an encrypted output of a fixed length. A hash is created using an algorithm and is essential to blockchain management in cryptocurrency. It helps in storing data of transaction (Time, Date, Who etc.). The blockchain technology is probably one of the most defining technological innovations of our time. It has changed the ways how digital transactions are managed and arranged. Hashing in blockchain refers to the process of having an input of whatever length reflecting an output item of a fixed length. Example : When you take video of 100 megabytes and hash it using SHA-256 the output will be a hash of 256-bits in length and if you take a video of 50 megabytes the output will be the same. The difference will lie on the hash pattern

Binary Search Tree

Binary Search Tree is one the data structures that features fast searching, sorting, easy insertion and deletion. Its also a sorted version of the binary tree. The tree works by appointing one node and the data following the node is separated by their amount. If the data is bigger than the node then the data goes to the right subtree and on the other hand, the smaller data goes to the left sub tree. The system works recursively so the sub-subbranch of the BST also sorts the data, which makes it easier to search.

Operations

In BST there is 3 operations which is find(x), insert(x), remove(x).

Find = finding the key (x) in the BST

Insert = inserting a new key (x) into the BST

Remove = removing key (x) from BST

·       Find

Because the BST sorts the data adequately, finding a key (x) is very easy. When we commence a search, we will begin at the root and the program will compare the key to the root. If the data is bigger than it will continue to the right subbranch after that it will also compare the key to the data on the right subbranch if the key is smaller than it will go to the left sub subbranch and so on.

·       Insert

When inserting data, the first data begin at the root if key is bigger than the root, insert to the right subbranch, repeat it until an empty node to put the key. Remember that the key will always be a new leaf.

·       Remove

In removing a node, there are three cases which needs to be considered. First, if the key is a leaf, the node can be deleted directly. Second, else if the key is a node with one child delete the node containing the key and connect the child with the new parents. Third, if the key is in a node which has two children, find the right most child of its left subbranch (z) and replace it the value (z) or alternately you can choose the left most child of its right sub tree.