Big Idea 3: Algorithms and Programming

The One Thing You Need to Know About This Big Idea:

3.1 Variables and Assignments

Key Ideas

• a variable is a placeholder for a value
• spelling and capitalization matter for variable names
• data types are different categories of data that your computer can represent

Vocabulary

• variable
• data types

Resources

3.2 Data Abstraction

Key Ideas

• elements are individual values in a list
• each element has an index value
• data abstraction simplifies a set of data by representing it in some general way

• data abstraction lets you create programs that are easier to build, maintain, and read

Vocabulary

• list
• element
• index
• string
• array

Resources

3.3 Mathematical Expressions

Key Ideas

• an algorithm represents the problem-solving logic
• programs execute algorithms
• steps in your algorithm are implemented in the order they're written in
• MOD operator
• evaluating an expression is done through an order of operations specified by the programming language

Vocabulary

• algorithm
• sequencing
• code statement
• expression

Resources

3.4 Strings

Key Ideas

• strings are an ordered list of characters that you can navigate through using index values
• you can't perform mathematical operations with strings, but you can still manipulate them
• slicing is the process to create a substring
• concatenation is the process of joining strings together

Vocabulary

• string concatenation
• substring

Resources

3.5 Boolean Expressions

Key Ideas

• Boolean variables can only represent the values true or false
• relational operators are used with Boolean values to test the relationship between two values
• NOT, AND, and OR are logical operators that evaluate either Boolean expressions or a single Boolean value

Vocabulary

• Boolean value

Resources

3.6 Conditionals

Key Ideas

• selection statements in programming are used to control the flow of execution in a program
• if statements and else statements execute different segments of code based on specified conditions

Vocabulary

• selection

Resources

3.7 Nested Conditionals

Key Ideas

• nested conditional statements are conditional statements inside conditional statements
• if the conditions for the outer conditional statement are not satisfied, the conditions for the nested conditional statement will not even be checked

Vocabulary

• nested conditional statements

Resources

3.8 Iteration

Key Ideas

• "repeat n times" loops happen a set number of times - these are for loops in Python
• "repeat until (condition)" loops happen until a condition is met - these are while loops in Python
• you can use logical operators when writing conditions for loops

Vocabulary

• iteration

Resources

3.9 Developing Algorithms

Key Ideas

• different algorithms can be used to achieve the same goals
• algorithms that look similar might yield different side effects or results
• new algorithms can be created from scratch or by combining and modifying algorithms that already exist

Vocabulary

Resources

3.10 Lists

Key Ideas

• there are basic operations you can perform on a list
  • access an element by index
  • assign the value of an element of a list to a variable
  • assign a value to an element
  • assign the value of one element in the list to another
  • insert elements at a given index
  • add elements to the end of the list
  • remove elements
  • determine the length of the list
• you can traverse through a list, either through a complete traversal or a partial traversal

Vocabulary

• traverse
• linear/sequential search

Resources

3.11 Binary Search

Key Ideas

• binary search algorithms eliminate half the data with each round of splitting
• data must first be sorted in order to use a binary search method

Vocabulary

• binary search

Resources

3.12 Calling Procedures

Key Ideas

• you use a procedure to use the same set of instructions without having to rewrite it into your code
• procedures often require some sort of parameter in order to work
• you call procedures with arguments
• once a procedure terminates (either because there are no more lines or you use a return statement), the program goes back to where the procedure was called and continues reading code sequentially

Vocabulary

• procedure
• parameters
• arguments

Resources

3.13 Developing Procedures

Key Ideas

• you can call a procedure without knowing how it works
• procedures allow you to solve a large problem based on the solution to smaller sub-problems
• procedural abstraction allows programmers the flexibility to modify or fix procedures without affecting the whole program, as long as the procedure continues to function in the same way

Vocabulary

• procedural abstraction
• modularity

Resources

3.14 Libraries

Key Ideas

• you can import already-existing code from a library to help you create new programs
• you can also import code you've already written
• APIs help you understand how the procedures in a library behave and how to use them

Vocabulary

• software library
• application program interface

Resources

3.15 Random Values

Key Ideas

• using random number generation in a program means we might get a different result every time we run the program

Vocabulary

Resources

3.16 Simulations

Key Ideas

• simulations are simplifications of complex objects or phenomena for a stated goal, such as investigating real-world events and conditions
• to develop a simulation, you have to remove certain real world details or simplify how something functions
• simulations run the risk of being too simple or conveying the wrong message about what you're trying to study
• simulations may contain bias based on what the creator chose to include or exclude

Vocabulary

• simulation

Resources

3.17 Algorithmic Efficiency

Key Ideas

• informally, efficiency is measured by determining how many times a statement or statement group executes
• algorithms that run with a polynomial efficiency or lower are said to run in a reasonable amount of time
• algorithms that run with an exponential or factorial efficiency run in an unreasonable amount of time
• some problems can't be solved in a reasonable amount of time, so we look for an approximate solution using a heuristic

Vocabulary

• problem
• instance
• decision problem
• optimization problem
• efficiency
• reasonable amount of time
• unreasonable amount of time
• heuristic

Resources

3.18 Undecidable Problems

Key Ideas

• an undecidable problem may be solvable for some cases, but there is no algorithm that will solve the problem in all cases

Vocabulary

• decidable problem
• undecidable problem

Resources

Exam Weighing:

• 30-35% of the AP Exam

• Practically, this translates to a good portion of the questions on the test. This unit also makes up the bulk of your final Create project. It's a big part of this course.