Data Structures, Algorithms, Programming Concepts (C/C++/Python/Java), OOP & Web Development (Part 7)

Question 1

In CSS cascading rules, which of the following styles has the HIGHEST specificity weighting when styling an HTML element?

Accepted Answer

Inline style attribute (e.g. `style="color: red;"`)

Answer

ID selector (`#title`)

Answer

Class selector (`.highlight`)

Answer

Element selector (`p`)

Question 2

What do HTTP status codes `200`, `404`, and `500` signify in web communications, respectively?

Accepted Answer

200: OK (Success); 404: Not Found (Client Error); 500: Internal Server Error (Server Error)

Answer

200: Created; 404: Unauthorized; 500: Gateway Timeout

Answer

200: Redirect; 404: Forbidden; 500: Bad Request

Answer

200: Server error; 404: OK; 500: Not found

Question 3

What is "Hoisting" in JavaScript?

Accepted Answer

The default JavaScript engine behavior of moving variable (`var`) and function declarations to the top of their containing scope during the compilation phase before code execution

Answer

Lifting HTML elements above other elements using CSS

Answer

Uploading files to a web server

Answer

Compressing JavaScript source code

Question 4

What is the purpose of "Header Guards" (`#ifndef HEADER_H`, `#define HEADER_H`, `#endif`) in C/C++ header files?

Accepted Answer

To prevent duplicate definitions and double-inclusion compilation errors when a header file is included multiple times across different source files

Answer

To encrypt the header file on disk

Answer

To prevent unauthorized users from reading the code

Answer

To speed up internet downloads

Question 5

What is the purpose of the `typedef` keyword in C and C++?

Accepted Answer

To create a new, user-friendly alias name for an existing data type (e.g. `typedef unsigned long int ulong;`)

Answer

To define a new hardware type

Answer

To create an array of functions

Answer

To delete variables from memory

Question 6

Which standard C library function in `<string.h>` is used to safely copy at most $N$ characters from a source string to a destination string buffer to avoid buffer overflows?

Accepted Answer

strncpy()

Answer

strcpy()

Answer

strcat()

Answer

strcmp()

Question 7

What is the result of evaluating the bitwise expression `5 ^ 5` (bitwise XOR of a number with itself) in C/C++?

Accepted Answer

0

Answer

5

Answer

10

Answer

1

Question 8

What is the mathematical equivalent of performing a Bitwise Left Shift by 1 bit (`x << 1`) and a Bitwise Right Shift by 1 bit (`x >> 1`) on a positive integer $x$?

Accepted Answer

`x << 1` multiplies $x$ by 2 ($x imes 2$); `x >> 1` performs integer division of $x$ by 2 ($x / 2$)

Answer

`x << 1` adds 1; `x >> 1` subtracts 1

Answer

`x << 1` squares $x$; `x >> 1` takes the square root

Answer

They both leave $x$ unchanged

Question 9

How does automatic "Garbage Collection" work in Java and Python runtimes?

Accepted Answer

The runtime environment automatically tracks and reclaims heap memory occupied by objects that are no longer referenced or reachable by any active thread in the program

Answer

It empties the computer's physical recycle bin

Answer

It deletes temporary internet files

Answer

It frees local variables on the call stack

Question 10

What is the time complexity of accessing an element in an array by its index versus accessing an element in a Singly Linked List at position $K$?

Accepted Answer

Array: O(1) (constant time); Linked List: O(K) (linear traversal time)

Answer

Array: O(N); Linked List: O(1)

Answer

Both are O(1)

Answer

Both are O(log N)

Question 11

What is the formal mathematical definition of Big-O notation ($f(n) = \mathcal{O}(g(n))$)?

Accepted Answer

There exist positive constants $c > 0$ and $n_0 \ge 1$ such that $0 \le f(n) \le c \cdot g(n)$ for all $n \ge n_0$ (Asymptotic Upper Bound)

Answer

There exist constants such that $f(n) \ge c \cdot g(n)$ (Lower Bound)

Answer

The function $f(n)$ is strictly equal to $g(n)$

Answer

The function $f(n)$ approaches zero as $n \rightarrow \infty$

Question 12

What does Big-Theta notation ($f(n) = \Theta(g(n))$) signify in algorithm complexity analysis?

Accepted Answer

An Asymptotically Tight Bound — there exist positive constants $c_1, c_2 > 0$ and $n_0 \ge 1$ such that $c_1 \cdot g(n) \le f(n) \le c_2 \cdot g(n)$ for all $n \ge n_0$

Answer

An asymptotic lower bound only

Answer

The best-case execution time

Answer

An exponential execution time

Question 13

Using the Master Theorem for divide-and-conquer recurrences, what is the asymptotic solution of the recurrence relation $T(n) = 2T(n/2) + \Theta(n)$ (the Merge Sort recurrence)?

Accepted Answer

T(n) = Θ(n log n)

Answer

T(n) = Θ(n^2)

Answer

T(n) = Θ(n)

Answer

T(n) = Θ(log n)

Question 14

What is the asymptotic solution of the recurrence $T(n) = 8T(n/2) + \Theta(n^2)$ using the Master Theorem?

Accepted Answer

T(n) = Θ(n^3)

Answer

T(n) = Θ(n^2 log n)

Answer

T(n) = Θ(n^2)

Answer

T(n) = Θ(n^4)

Question 15

Why does standard "Merge Sort" require $\mathcal{O}(N)$ additional auxiliary memory space, whereas "Quick Sort" requires only $\mathcal{O}(\log N)$ stack space?

Accepted Answer

Merge Sort requires an auxiliary temporary array of size $N$ to merge two sorted subarrays back together in linear time; Quick Sort partitions elements in-place

Answer

Quick Sort uses hard drive memory

Answer

Merge Sort is an unstable sort

Answer

Quick Sort cannot sort strings