Responsive design Responsive design means that a web page can automatically stretch or shrink depending on the screen is displayed on. Phone, tablet and computer screens, including the one you’re...

Name Resolution Domain name system (DNS) DNS is a global and highly distributed network service that resolves strings of letters into IP addresses for you. Let’s say you wanted to check a wea...

DOM When your web browser receives an HTML page, it constructs a DOM to represent it. DOM stands for Document Object Model and it is simply a tree, structure or model of the objects in your HTML ...

4Sum II Given four integer arrays nums1, nums2, nums3, and nums4 all of length n, return the number of tuples (i, j, k, l) such that: 0 <= i, j, k, l < n nums1[i] + nums2[j] +...

The TCP/IP five network model   Layer Protocal Content Address 5 Application HTTP, SMTP, etc… Message n/a ...

What is HashTable Official definition: A hash table is a data structure that allows direct access based on the value of the key. To put it simply, an array is actually a hash table. In a hash...

Swap Nodes in Pairs Given a linked list, swap every two adjacent nodes and return its head. You must solve the problem without modifying the values in the list’s nodes (i.e., only nodes themsel...

Linked List What is Linked List? Linked List is a linear data structure in which elements are not stored at a contiguous location, rather they are linked using pointers. Linked List forms a seri...

Remove Linked List Elements Given the head of a linked list and an integer val, remove all the nodes of the linked list that has Node.val == val, and return the new head. Method one: Why we ...

Squares of a Sorted Arrays Given an integer array nums sorted in non-decreasing order, return an array of the squares of each number sorted in non-decreasing order. The ordinary method is to ...