# Basic CS [TCS Placement]: Sample Questions 3 - 4 of 196

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## Question 3

Basic CS

### Explanation

- VRC or vertical redundancy check or the partial check is least expensive mechanism for error detection.
- The redundant bit called parity bit is appended to every data unit so that the total number of 1՚s in the unit becomes even.

- VRC can detect all single bit error
- Can detect burst errors if the total number of errors in each data unit is odd.
- VRC can՚t detect errors where the total number of bits changed is even.

## Question 4

Basic CS

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### Describe in Detail

Essay▾In tree construction which is the suitable efficient data structure? (Array, Linked list, stack, Queue)

### Explanation

- In tree construction linked list is efficient data structure
- Linear data structure where each element is a separate object.

- Each element of a list comprises of two items - the data and a reference to the next node.
- The last node has a reference to null. The entry point into a linked list is called the head of the list- head is not a separate node, but the reference to the first node. If the list is empty then the head is a null reference.
- A linked list is a dynamic data structure- number of nodes in a list is not fixed and can grow and shrink on demand.
- Any application dealing with unknown number of objects like in a tree should use a linked list.
- Diagram shows the linked list implementation of a binary tree.