Novigo Integrated Services Interview Questions and Answers

Questions related to JavaScript and web development

• let, const, and var are used to declare variables in JavaScript with different scoping rules

• Virtual DOM is a lightweight copy of the actual DOM used for efficient rendering in React

• Hooks are functional components in React that allow for state management and lifecycle methods

• Redux is a state management library for JavaScript applications

• API calling via Redux involves dispatching actions to update the store with data from an AP...read more

Typecasting is converting one data type to another. Malloc and calloc are functions used to allocate memory dynamically.

• Typecasting is done using casting operators like (int), (float), etc.

• Malloc is used to allocate memory for a single variable while calloc is used to allocate memory for multiple variables.

• Malloc and calloc return a void pointer which needs to be typecasted to the appropriate data type.

• Example: int x = (int) 3.14; // typecasting float to int

• Example: int *arr ...read more

Linkedlists are a data structure where each element points to the next element. Arrays are a data structure where elements are stored in contiguous memory locations.

• Linkedlists are dynamic in size, while arrays have a fixed size.

• Insertions and deletions are faster in linkedlists compared to arrays.

• Example: Linkedlist - 1 -> 2 -> 3 -> null, Array - [1, 2, 3]

• Arrays can be accessed randomly using indexes, while linkedlists need to be traversed sequentially.

useState is a hook in React that allows functional components to have state.

• useState is a hook provided by React for managing state in functional components.

• It returns an array with two elements - the current state value and a function to update that value.

• Example: const [count, setCount] = useState(0);

• The initial state value is passed as an argument to useState.

Code snippet for useEffect hook in React

• UseEffect is a hook in React that allows you to perform side effects in function components

• It runs after every render and can be used for data fetching, subscriptions, or manually changing the DOM

• Example: useEffect(() => { console.log('Component rendered') }, [])

Knapsack problem is a dynamic programming problem where we have to maximize the value of items in a knapsack with a given weight limit.

• Divide the problem into subproblems and solve them recursively

• Use memoization to avoid solving the same subproblem multiple times

• Start with the base case and build up to the final solution

• Examples: 0/1 Knapsack problem, Fractional Knapsack problem

Reverse a linked list

• Traverse the linked list and change the direction of the pointers

• Use three pointers to keep track of current, previous and next nodes

• Handle the edge cases of empty list and single node list