## Introduction to Arrays
An **Array** is a fundamental, linear data structure that stores a collection of elements of the same data type in contiguous (adjacent) memory locations.
Instead of declaring separate variables for twenty different integers, you declare a single array variable and access each individual element using an **index** (a numerical position offset).
## Linear Arrays
A **Linear Array** (or one-dimensional array) is a list of a finite number of homogenous data elements such that:
1.
## What is a Data Structure?
At its core, a **Data Structure** is a systematic way of organizing, managing, and storing data in a computer so that it can be accessed and modified efficiently.
Instead of just scattering numbers or text randomly in a computer's memory, a data structure gives that data a specific shape and structure based on how we plan to use it. For example, if you need to reverse a word, storing the letters in a structure that lets you pull them out from last-to-first makes the job
## Qualitative vs. Quantitative Research
Research approaches are broadly divided into two major paradigms: **Qualitative** and **Quantitative**. The choice between them depends entirely on your research objectives, the nature of your data, and whether you are trying to *explore a concept* or *test a theory*.
| Feature | Qualitative Research | Quantitative Research |
|---|---|---|
| **Core Objective** | To understand underlying reasons, opinions, meanings, and social experiences. | To quantify data,
1. The Benefits of Learning Foreign Languages
Nowadays, learning foreign languages is extremely important in our globalized world. Languages connect people, cultures, and countries, making communication easier and more effective.
First of all, multilingualism improves career opportunities. Many international companies prefer employees who can communicate with foreign partners and clients. Knowledge of English, Spanish, French, or Mandarin significantly increases professional mobility and competitiveness
## Part 1: Sampling Design and Sampling Procedure
In research, it is usually impossible, too expensive, or too time-consuming to collect data from every single individual in a population (referred to as a **census**). Instead, researchers select a smaller, representative subset of that population, known as a **sample**.
* **Population (N):** The total collection of all elements that share a common set of characteristics (e.g., all BBA students in a university). **Sample (n):** The actual group
## Part 1: Research Fundamentals :Research is a systematic, deliberate, and detailed study done to discover new facts, verify existing knowledge, and reach new conclusions. It is essentially a structured journey from the known to the unknown.
### Characteristics of Research :For an investigation to be considered true research, it must possess the following core traits: * **Empirical:** It is based on direct experience or observation by the researcher, rather than mere speculation or hearsay. *
accent — The characteristic pronunciation patterns of a variety of speech.
accommodation — The phenomenon in which speakers change their manner of speaking depending on whom they interact with.
acquiring (language) — The natural acquisition of a language variety.
active knowledge — Knowledge of a language that includes the ability to use and produce it.
age-grading — Variation in language use associated with different ages.
apparent time — A method of studying language change by comparing
Q1. Explain DES Structure.
DES (Data Encryption Standard) is a symmetric key block cipher used for data encryption. It encrypts 64-bit plaintext using a 56-bit secret key.
DES uses a 16-round Feistel structure. The plaintext first undergoes initial permutation and is divided into left and right halves. In every round, the right half is processed using a round function and XORed with the left half. After 16 rounds, final permutation is performed to generate ciphertext.
def removeDuplicates(self, s: str, k: int) -> str:
stack = []
for char in s:
if not stack:
stack.append((char, 1))
else:
last_char, last_cnt = stack[-1]
if char != last_char:
stack.append((char, 1))
else:
if last_cnt + 1 < k:
stack[-1] = (last_