3i Infotech Papers: Sample Questions 848 - 850 of 1245

Examrace Placement Series prepares you for the toughest placement exams to top companies.

Question number: 848

» Basic CS » Data Structures

MCQ▾

Question

Of the following tree structure, which is, efficient considering space and time complexities?

Choices

Choice (4) Response

a.

Complete Binary Tree

b.

Incomplete Binary Tree

c.

Full Binary Tree

d.

None of the above

Answer

a.

Explanation

Complete or perfect Binary Tree

  • A binary tree in which every level, except possibly the last, is completely filled.

  • Generalization: Complete tree, binary tree.

  • Specialization: Binary heap, perfect binary tree.

Graph shows the complete binary tree

Graph Shows the Complete Binary Tree

Graph shows the complete binary tree

  • A complete binary tree has nodes at every depth k < n.

  • A complete binary tree of depth n has nodes.

  • Efficiently implemented as an array- a node at index i has children at indexes and and a parent at index , with 1-based indexing.

  • If child index is greater than the number of nodes, the child does not exist.

Question number: 849

» Database » MySQL

Short Answer Question▾

Write in Short

What are the tadeoffs with having indexes?

Explanation

  1. Faster selects, slower updates.

  2. Extra storage space to store indexes. Updates are slower because in addition to updating the table you have to update the index.

Question number: 850

» Basic CS » Operating System

Short Answer Question▾

Write in Short

What is buffer cache?

Explanation

Define buffer cache

Define Buffer Cache

Define buffer cache

  • Files are stored on hard drive- processes can access these files and create new files.

  • When process requests a file the kernel brings the file into the main memory where user process can change, read, or access the file.

  • The memory location where the file is brought is called the buffer cache.

  • The buffer cache can be regarded as a memory resource- primarily an I/O resource mediating data transfer.

  • A write request can thus be satisfied without accessing the physical device- kernel checks the buffer cache to see if the block, containing the data address, is already in memory.