Notes, summaries, assignments, exams, and problems for Computer science

Problem Statement 16: Coin Change

Given a set of coins and a value, find the minimum number of coins to satisfy the given value.

Test Case 1:

Coins: {25, 20, 10, 5}, Value: 50 cents

Used coin: 25 cents

Used coin: 25 cents

Total number of coins: 2

Test Case 2:

Coins: {25, 20, 10, 5}, Value: 73 cents

Used coin: 25 cents

Used coin: 25 cents

Used coin: 20 cents

Used coin: 3 cents

Total number of coins: 4

Code:

-
#include int main { int amount =
50; int coins[] = {25, 20, 10, 5}; int
numCoins = 0;
printf("Amount: %d cents\n", amount);
for (int i = 0; i while (amount >= coins[i]){
amount -= coins 1;
numCoins++；
printf("Used
coin: %d cents\n", coins[i]);
}
printf("Total number of coins: %din", numCoins); return 0; }

Problem Statement 19: -#include #include int i,j,k,...

Bisection Method Implementation

#include <stdio.h>
#include <math.h>

#define f(x) (cos(x) - (x * exp(x)))

int main() {
    float x0, x1, x2, f0, f1, f2, e;
    int step = 1;

    /* Inputs */
    up:
    printf("\nEnter two initial guesses:\n");
    scanf("%f%f", &x0, &x1);
    printf("Enter tolerable error:\n");
    scanf("%f", &e);

    f0 = f(x0);
    f1 = f(x1);

    if (f0 * f1 > 0.0) {
        printf("Incorrect Initial Guesses. Try again.\n");
        goto up;
    }

    printf("\nStep\t\tx0\t\tx1\t\tx2\t\tf(x2)\n");
    do {
        x2 = (x0 + x1) / 2;
        f2 = f(x2);
        printf("%d\t\t%f\t%f\t%f\t%f\n", step, x0, x1, x2, f2);

        if (f0 * f2 < 0) {
            x1 = x2;
            f1 = f2;

Software Design Patterns and Architecture (CSC3324)

Defining Software Design Patterns

• A reusable solution to a recurring design problem.

• It reuses abstract knowledge about problems and solutions.

• Independent of specific implementations, it acts as a template.

• It utilizes Object-Oriented Programming (OOP) features such as inheritance and polymorphism.

The Christopher Alexander Definition

“Each pattern describes a problem which occurs over and over again... and then describes the core of the solution... you can use this solution a million times over without doing it the same way twice.”

Architecture vs. Design Patterns

Python Operations and Operators

This section covers fundamental operations and operators in Python, which are symbols used to perform operations on values and variables.

# Examples of different operators
a = 10 // 3  # Floor Division
a = 10 % 3   # Modulo Operator
a = 3        # Assignment
b = 1        # Declaring variables
a == b       # Comparison

Types of Operators

Operators are used for operations between values and variables. The main types are:

• Assignment Operators: Used to assign values to variables.
• Logical Operators: Used to combine conditional statements.
• Comparison Operators: Used to compare two values.
• Arithmetic Operators: Used with numeric values to perform common mathematical operations.
• Bitwise Operators: Used to compare binary numbers.

Core Goals of a DBMS

A robust database management system (DBMS) provides software tools for the efficient storage, retrieval, manipulation, security, and administration of data. Key objectives include:

• Ensuring data integrity and security
• Supporting concurrent access
• Providing data abstraction
• Optimizing query processing

Entity Relationships and Cardinality

Strong vs. Weak Entities

An entity denotes a distinct object, while an entity type defines its category and an entity set aggregates objects belonging to that category. A strong entity has its own primary key, whereas a weak entity lacks its own and depends on a foreign key from a strong entity (e.g., order items for an order).

Cardinality

Cardinality represents the uniqueness and number of elements...

Bitcoin Consensus

The Problem: Decentralized Network

• Bitcoin operates without a central authority; all users must agree on transaction history.
• It faces the Byzantine Generals Problem; although unknown to each other, participants must establish trust.
• Trust is established using consensus protocols, incentives, and cryptography.

How It Works

• The Bitcoin algorithm operates on nodes.
• Any device (computer) running the full Bitcoin software and connected to the internet acts as a connection point for creating blocks and verifying transactions.
• When a block is created, nodes communicate to verify the transactions and ensure they follow the algorithm's rules.
• Each node maintains a complete copy of the Bitcoin blockchain.

Participants in the Ecosystem

• Full Nodes:

Jose Andres Gutierrez Vargas

Email: [email protected]
Phone: [Your Phone Number]

Professional Summary

Results-driven and highly motivated Software Developer with extensive expertise in backend and frontend development, RESTful APIs, and database management. Skilled in SQL and NoSQL databases, with in-depth experience in Node.js for building scalable and high-performance applications. Adept at optimizing system performance, troubleshooting technical issues, and implementing innovative solutions.

Former Frontend Developer at Google, where I contributed to the development of dynamic and interactive web applications, enhancing user experiences through cutting-edge technologies. Passionate about software development, staying updated with the latest...

1. PIC18 Architecture Details

• Harvard Architecture

  Features distinct program memory and data memory. Includes the MPU, Program Memory, Data Memory, I/O Ports, and support devices like timers.

• Microprocessor Unit (MPU)

  • ALU (Arithmetic Logic Unit)

    Performs operations such as addition, subtraction, and logical operations.

  • Registers

    Includes WREG (8-bit accumulator), Program Counter (PC), Stack Pointer (SP), and File Select Registers (FSRs).

  • Memory

    Offers 2 MB of program memory and 4 KB of data memory.

  • Bank Switching

    Data memory is divided into 16 banks, with one 256-byte access bank.

2. Data Formats and Representations

• Unsigned Integers

  These are 8-bit values, ranging from 0 to 255.

• Signed Integers

  Represented using 2's complement, with a range from -128 to

Core Software Design Principles

• Abstraction: Removal or masking of detail and complexity.
• Modularity: Software is divided into separately named and addressable components.
• Separation of Concerns: Any complex problem can be more easily handled if it is subdivided into pieces.
• Information Hiding / Encapsulation: Hide implementation details from client components; communicate only via controlled interfaces.
• High Cohesion: Components provide specific functionality.
• Low Coupling: Components have as few dependencies as possible so they can change with minimal impact on other components.

SOLID Principles

Single Responsibility Principle

The idea here is simple: Separate the code that supports different actors (i.e., users, stakeholders, or client components)...