Python Programming

For a good four years or so, I had a Python tutorial for beginners hosted on CodinGame. As of 2026, CodinGame has announced that "Playgrounds and the tech.io platform are currentlyh entering deprecation, and will be partially or completely removed in the future." Here is the link: https://www.codingame.com/playgrounds/64843/beginner-python-concepts/intro

As of June 21st, 2026, I have copied the contents of that playground and pasted it here as comments. I intend on formatting and adding it all here for (hopefully) a more persistent and lasting platform.

This is to keep track of my CodinGame playground: Beginner Python Concepts. It's still up, but they disabled the functionality to run the code in the browser. 1/13 Intro ---------------------------------------------------------------------------------------------------------- Intro Hello and welcome to Beginner Python Concepts! Before we get started with actual Python code, it's important to understand what programming is all about. Simple Machines Now, computers are very complex, but the way they operate is about as simple as you can get. They deal in 0s and 1s, and they only do exactly what they're told to. There is no thinking / interpreting / assuming with computers. If you make a mistake, the computer will still follow your poorly written instructions. Some Perspective Think about any mundane task. This could be going upstairs, packing a bag for a vacation, or even driving to the post office. When you describe how to do these tasks to other people, you can skip over what we consider "common sense." If your bathroom is upstairs and your guest asks to use it, you just tell them it's upstairs. Maybe you tell them to jiggle the toilet handle if it sticks or it's the second door on the right. However, you don't have to tell them things like "watch out for my dog" or "if the door is closed, there might be someone in it already." Now, with computers, you have to tell them EXACTLY what to do and how to do it. If you don't tell them to watch out for your dog, they would encounter the dog and crash. If the bathroom was occupied, they would crash. If you had too much stuff in the travel bag, they would keep filling it and crash. If you didn't tell them where the post office is, they would wander and probably crash. These are exaggerations, as what computers need to do is much simpler as far as tasks go. At the basic level, computers are just locating, calculating, or saving data. That's it. We've come so far as to be able to represent just about anything as data. My YouTube Channel I make educational and gaming videos as A-Rye on YouTube: https://www.youtube.com/@a-rye If you get stuck, I recommend the video I made streaming the creation of this playground: https://www.youtube.com/watch?v=X8Vu-nEtMVA Here is my playlist for learning beginner Python programming: https://youtube.com/playlist?list=PLrUDqFPKLyT0hyTCzZeU9xYRXLTTLpoCk&si=56PujyQydBEsif2w Solidify Your Understanding by Creating Your Own Playground! For anyone interested in making their own CodinGame Playground, I streamed the making of this via Twitch and saved the videos via YouTube. You can follow along with the video above and the one below. If you have any questions, ask the CodinGame community through their Discord chat! You can also shoot me questions on my Twitch streams or comment on my YouTube videos. The best way to learn new concepts is to be able to teach said concepts to others. Even if you're just talking to your Rubber Duck, being able to teach the material bodes well for your understanding. For the second part video of this playground, visit YouTube here: https://www.youtube.com/watch?v=hCZ4EUrBJC4 2/13 Hello World ---------------------------------------------------------------------------------------------------------- Hello World This is the classic "Hello World" program in Python. This will print whatever String (array of chars / group of letters) you have between the single (' ') or double quotes (" ") Hello World! 12 print("Hello World!") Being able to print output is very important in coding. You can use print statements to see the values of variables, if sections of code are being executed, or the results of your algorithm. Formatting is a major part of problem solving with code. String manipulation can be done a few ways in Python print("Hello! " * 3) For the rest of the examples, let's declare a String variable to use test_string = "Hello World, but now our new string!" Slicing is where you target or work with only parts of a string. To do this, use square brackets ([]). Within the square brackets you can set the start, stop, and step. Or in other words, the starting point, ending point, and how much to count by print(test_string[1:6]) Print every other letter print(test_string[::2]) Reverse the string print(test_string[::-1]) Print single char at a certain index print(test_string[0]) This also works backwards with a negative index print(test_string[-1]) print(test_string[-5]) Set the start point as the fifth character from the end print(test_string[-5:]) print(test_string[-10:-3]) Try them! 1234567891011121314151617181920212223242526272829303132 print("Hello! " * 3) print("For the rest of the examples, let's declare a String variable to use") test_string = "Hello World, but now our new string!" print("Try slicing different parts of the string") print(test_string[1:6]) print("Print every other letter") print(test_string[::2]) print("Reverse the string") print(test_string[::-1]) print("Print single char at a certain index") print(test_string[0]) print("This also works backwards with a negative index") print(test_string[-1]) print(test_string[-5]) print("Set the start point as the fifth character from the end") print(test_string[-5:]) print(test_string[-10:-3]) 3/13 Comments ---------------------------------------------------------------------------------------------------------- Comments Comments are very useful in programming. If you're coding for work or to be published, you'll want to explain your code with comments. You can also use comments in debugging to investigate your code further. # This is a single line comment. Any line that starts with a # will be seen as a comment by the compiler / interpreter / computer. ''' This is a multi line comment ''' """ This is also a multi line comment """ # It gets a weird value here, still not sure why? Disabling parts of your code Sometimes, you just want a part of your code to stop temporarily. I often find myself doing this when trying to optimize my code or when trying to single out a corner case in my code. Let's take that mass of code from the previous page and try looking at each piece individually. Try "turning pieces on and off again"! 123456789101112131415161718192021222324252627282930313233 print("Hello! " * 3) # print("For the rest of the examples, let's declare a String variable to use") test_string = "Hello World, but now our new string!" print("Try slicing different parts of the string") print(test_string[1:6]) # print("Print every other letter") # print(test_string[::2]) # print("Reverse the string") # print(test_string[::-1]) # print("Print single char at a certain index") # print(test_string[0]) # print("This also works backwards with a negative index") # print(test_string[-1]) # print(test_string[-5]) 4/13 Primitive Variables ---------------------------------------------------------------------------------------------------------- Primitive Variables Primitive Variables are simple, single value variables used in computing. Think of them as shipping boxes to contain data. You need the right type of shipping box / container for different types of data. Now, with Python, it's harder to see what type a variable is. Python does not require you to declare the type of variable when declaring Primitive variables (as opposed to objects). Strings / Arrays of Chars = "Hello World!" / "This is also a string" / Any group of characters contained in single ('') or double ("") quotes Chars / Characters = 'a', 'b', 'Z', '!' / Any single letter or character. Can be in single or double quotes (for Python, not necessarily other languages) Ints / Integers = 5 / 4 / 5,000,000 / any whole number Float / Floating Point = 10.0 Bool / Boolean = True / False To see what type your variable is, use the built-in type() function. 123456789101112 example_string = "Hello World!" example_char = 'a' example_int = 5 example_float = 10.0 example_boolean = True print(type(example_string)) print(type(example_char)) print(type(example_int)) print(type(example_float)) print(type(example_boolean)) 5/13 Functions ---------------------------------------------------------------------------------------------------------- Functions Functions are sections of code that are meant to accomplish one (or few) action(s). Functions are used to organize code, as well as allow for modularity. Modularity means that code can be reused with little to no adjustments. When defining a function, you start with the keyword "def", followed by the name of the function and attached parameters / arguments for the function, and finally a colon (:). Any code that is meant to be contained in the function needs to be indented one indent further than the function declaration line. Try changing the values for each of the functions! 123456789101112131415161718192021222324252627 def multiply(a, b): return a*b # A single '/' will yield a float / partial / decimal point having number. def divide(a, b): return a/b # A double '/' will yield an integer / whole number answer. def integer_divide(a, b): return a//b def add(a, b): return a+b def subtract(a, b): return a-b def modulo(a, b): return a%b print(multiply(2,5)) print(divide(10,3)) print(integer_divide(10,3)) print(add(2,40)) print(subtract(5,2)) print(modulo(10,3)) def multply(a, b): return a*b In this example, the declaration line is "def multiply(a, b):". This means that we have a function named "multiply" that takes two arguments, "a" and "b". The next line returns the value of the two input arguments when they are multiplied together (or the product of the two inputs). To call a function, we would do something like this: multiply(2, 5) Notice that you don't actually see anything in your terminal / output. This is because the nature of this function simply multiplies the arguments and returns the product. If we want to see what value is returned from this function, we would need to either print our call to that function, or add print functionality within the function. print(multiply(2, 5) Or def multply(a, b): print(a*b) return 0 Either way, we need to define our function BEFORE we try to call it / envoke it / run it. The compiler / interpreter / computer reads our code top down, left to right. This means that if we try to call our function before we define it, we will get an error. The computer doesn't know what we're talking about and will ask us to clarify. 6/13 Control Flow ---------------------------------------------------------------------------------------------------------- Control Flow Control Flow refers to the use of comparison logic to determine what to do next. By that, I mean using if, elif, else statements to filter what code to run based on certain conditions. The test cases provided test some of the common "corner cases" you may want to test. 1234567891011121314151617181920212223 def control_flow(score): if score >= 90: return "A" elif score >= 80: return "B" elif score >= 70: return "C" elif score >= 60: return "D" else: return "F" print(control_flow(1000000)) print(control_flow(95)) print(control_flow(90)) print(control_flow(89)) print(control_flow(85)) print(control_flow(75)) print(control_flow(65)) print(control_flow(59)) print(control_flow(0)) print(control_flow(-1000)) If and elif statements will execute if the expression equates to True or 1. If the expression evaluates down to any other value, the attached code won't execute. Here are some examples of such: 123456789101112131415 the_meaning_of_life = 42 valid = False if the_meaning_of_life == 42: print("Ran") if 1: print("1 worked as well!") if valid: print("It's valid") else: print("It's not valid") You can also chain conditions in your if, elif, else statement blocks. This can be done with and, or, not, and xor. Try changing the conditions 1234567891011121314151617 my_int = 5 if my_int < 10 and my_int > 0: print("It's between 0 and 10") my_char = 'c' to_search = "Does this string have your letter?" if my_char not in to_search: print("Nope, my char is not in there!") if my_char not in to_search or 1: print("Either part can be true") if my_char not in to_search or 1 or my_int < -1000: print("You can have as many conditionals as you want!") 7/13 Loops ---------------------------------------------------------------------------------------------------------- Loops Loops are very useful when needing to do the same action multiple time (iterations). For loops are usually better when the amount of iterations is known and while loops are usually better when the number of iterations is not known. However, you can pretty much do any process (algorithm) with either style of loop. You can also use recursion. Iterate through every char in a string Try changing the string! 1234 test_str = "Hello World!" for char in test_str: print(char) Indexes are used to keep track of what we're working with for each iteration. With while loops, you have to manually change the index. Be careful, infinite loops are created when a terminating condition is never met. IE the index never changes, a count never changes, or whatever condition we decide for the loop. Try adjusting the index! 1234567 index = 0 test_str = "Hello Other World!" while index < len(test_str): print(test_str[index]) index += 1 In other languages, there are do while loops. However, Python doesn't use them without some extra effort. You can also use the range() function to set a start, stop, and step for your for loops. This is similar to the start, stop, and step of string slicing. Start is the initial value that the loop range will start at. Stop is the end limit that the loop value will reach in the range. Step is the amount that the loop will count by. Try changing n! 12345 n = 100 for num in range(1,n+1,2): print(num) Here is a nifty way to demonstrate Multiplication and Division as loops of Addition and Subtraction! Try me! 12345678910111213141516171819202122 # Multiplication to_mult = 5 mult_times = 10 mult_ans = to_mult for num_m in range(1,mult_times): mult_ans += to_mult print(mult_ans) # Division to_div = 50 div_times = 5 div_ans = div_times div_count = 0 while div_ans <= to_div: div_ans += div_times div_count += 1 print(div_count) 8/13 Recursion ---------------------------------------------------------------------------------------------------------- Recursion To demonstrate recursion, we need to define a function. The concept is where we have a function that calls itself until a condition is met. It's also easy to write infinite loops with recursion. The condition needing to be met is known as the Base Case. Once we reach that Base Case, we return all the data we've calculated. Try it out here! 12345678910111213 test_str = "Hello World!" def recurse_this(n): if n == 1: print(test_str[len(test_str) - n]) print("This is the base case!") else: print(test_str[len(test_str) - n]) #print("iteration: " + str(n)) recurse_this(n-1) recurse_this(len(test_str)) 9/13 Examples of Loops ---------------------------------------------------------------------------------------------------------- Loop Examples It's helpful to see a few of the ways we would want to use these concepts. So, this bit of code here: This is written out, verbatum, what is going on in loop logic 1234567891011121314151617181920212223242526 my_str = "My String!" upper_case_count = 0 if my_str[0].isupper(): upper_case_count += 1 if my_str[1].isupper(): upper_case_count += 1 if my_str[2].isupper(): upper_case_count += 1 if my_str[3].isupper(): upper_case_count += 1 if my_str[4].isupper(): upper_case_count += 1 if my_str[5].isupper(): upper_case_count += 1 if my_str[6].isupper(): upper_case_count += 1 if my_str[7].isupper(): upper_case_count += 1 if my_str[8].isupper(): upper_case_count += 1 if my_str[9].isupper(): upper_case_count += 1 print(upper_case_count) Can be simplified with using loops, like so: Much more compact code 123456789 my_str = "My String!" upper_case_count = 0 for char in my_str: if char.isupper(): upper_case_count += 1 print(upper_case_count) Another nifty thing you can accomplish with a bit of loop logic and Python keyword shortcuts: This is some basic pattern matching 123456789101112 vowels = "aeiouAEIOU" my_str = "This is my string!" vowel_count = 0 for char in my_str: if char in vowels: vowel_count += 1 print(vowel_count) 10/13 Data Structures ---------------------------------------------------------------------------------------------------------- Data Structures Data structures are objects, which means they are more complex variables. All objects can technically be considered data strucures, as they can hold more data than primitive variable. However, most Computer Scientists are referring to objects like Lists / Arrays, Dictionaries, Trees, Graphs, Etc when discussing data structures. Arrays are groups of primitive variables all stored together. In Python, we refer to these as lists. Here are a couple of examples of lists: example_list = [] example_list_2 = [1,2,3] example_list_3 = ['a','b','c'] example_list_4 = [1, 'b', 3] To add elements to a list, use the .append() function. To access specific items in a list, you can use an index. Try adding, accessing, and removing elements from this list! 12345678910111213 example_list = [] example_list.append(1) print(example_list) example_list.append(2) example_list.append(3) print("First item at index 0: " + str(example_list[0])) print("First item at index 1: " + str(example_list[1])) print("First item at index 2: " + str(example_list[2])) print(example_list) To sort a list, use the .sort() or sorted() functions. Try adding, accessing, and removing elements from this list! 12345678910111213141516 to_sort = [9,8,7,6,5,4,3,2,1] print("Just using sorted(), which sorts the list for use but doesn't ACTUALLY sort the data stored in the variable") print(sorted(to_sort)) print(to_sort) print() print("Assigning the sorted version of the list to a new list variable") sorted_list = sorted(to_sort) print(sorted_list) print() print("Using .sort()") to_sort.sort() print(to_sort) Dictionaries are Python's answer to Switch Statements. The logic of a dictionary is to return a value based on an input value / key. In other languages, Switch Statements are used to accomplish similar logic. Here are a couple examples of dictionaries: alphabet_dict = { 'a':1,'b':2,'c':3,'d':4,'e':5,'f':6,'g':7,'h':8,'i':9,'j':10 ,'k':11,'l':12,'m':13,'n':14,'o':15,'p':16,'q':17,'r':18 ,'s':19,'t':20,'u':21,'v':22,'w':23,'x':24,'y':25,'z':26 } number_dict = { 1:'a',2:'b',3:'c',4:'d',5:'e',6:'f',7:'g',8:'h',9:'i',10:'j' ,11:'k',12:'l',13:'m',14:'n',15:'o',16:'p',17:'q',18:'r' ,19:'s',20:'t',21:'u',22:'v',23:'w',24:'x',25:'y',26:'z' } Dictionaries are created in a similar way to lists. Try adding, accessing, and removing elements from this dictionary! 123456789101112131415 example_dict = {} #to_add = letter_dict = {} alphabet = "abcdefghijklmnopqrstuvwxyz" for char in alphabet: if char in letter_dict: letter_dict[char] += 1 else: letter_dict[char] = 1 print(letter_dict) Lists of Lists 2D Arrays are commonly used in coding. In Python, this can be thought of as a list of lists. Try accessing and setting different values in the list of lists! 12345678910111213141516171819202122232425262728 my_list = [] my_list_of_lists = [] width = 7 height = 5 for num in range(height): for n in range(width): my_list.append(n) my_list_of_lists.append(my_list) my_list = [] for item in my_list_of_lists: print(item) print() x = 0 y = 0 # Try adjusting the coordinates by adjusting x and y. print(my_list_of_lists[y][x]) n = 3 n_2 = 2 # Or, you can change n or n_2 to change coordinates. print(my_list_of_lists[y+n][x+n_2]) 11/13 Example Algorithms ---------------------------------------------------------------------------------------------------------- Example Algorithms Explained Here are some example algorithms to see these Python concepts in use. ROT13 ROT13 stands for rotation of 13 values. This means that every character / letter in the plain text will be changed / encrypted to a different character 13 values away. 13 is the classic beginning number for a rotation encryption algorithm due to the nature of being able to decrypt the cipher text simply by encrypting the cipher text again with the same ROT13 algorithm. This is also known as Symmetric Encryption. Click "Reset Code" to get the original code example back. Try it out! 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051 def rot13(plain_text): alphabet_dict = { 'a':1,'b':2,'c':3,'d':4,'e':5,'f':6,'g':7,'h':8,'i':9,'j':10 ,'k':11,'l':12,'m':13,'n':14,'o':15,'p':16,'q':17,'r':18 ,'s':19,'t':20,'u':21,'v':22,'w':23,'x':24,'y':25,'z':26 } number_dict = { 1:'a',2:'b',3:'c',4:'d',5:'e',6:'f',7:'g',8:'h',9:'i',10:'j' ,11:'k',12:'l',13:'m',14:'n',15:'o',16:'p',17:'q',18:'r' ,19:'s',20:'t',21:'u',22:'v',23:'w',24:'x',25:'y',26:'z' } # other_dict = { # 0:'0',1:'1',2:'2',3:'3',4:'4',5:'5',6:'6',7:'7',8:'8',9:'9' # ,10:':',11:';',12:'<',13:'=',14:'>',15:'?',16:'@',17:'!',18:'"' # ,19:'#',20:'$',21:'%',22:'&',23:'\'',24:'(',25:')' # } # other_other_dict = { # 0:'*',1:'+',2:',',3:'-',4:'.',5:'/' # } found = False #found_2 = False cipher_text = "" new_index = 0 capitalized = False new_char = ' ' for char in plain_text: # Check for capitalization and set capitalized accordingly if char.isupper(): capitalized = True # Check if char is in alphabet_dict and assign index if so if char.lower() in alphabet_dict: new_index = int(alphabet_dict[char.lower()]) + 13 found = True # If the char is in other_dict, set found_2 to True # if char.lower() in other_dict: # #new_index = int(alphabet_dict[char.lower()]) + 13 # found_2 = True # If the new index is larger than 26, wrap around from the beginning if new_index > 26: new_index %= 26 # Build the return string based on if capitalized and found if capitalized and found: cipher_text += number_dict[new_index].upper() elif found: cipher_text += number_dict[new_index] else: cipher_text += char # elif found2: # print("It's found2") # else: # if char in other: # print(ok) # elif char in other_2: # print(ok) # else: # cipher_text += char capitalized = False found = False #found_2 = False #print("DEBUG") return cipher_text print(rot13("Uryyb jbeyq!@#$%^&*()_+-=/\\<>?,.~`")) print(rot13("Hello world!@#$%^&*()_+-=/\\<>?,.~`")) The concept of a circular array is demonstrated with these lines: if new_index > 26: new_index -= 26 So, even if the new index is too large to find the corresponding cipher text character, the index is adjusted to create the illusion of a circular array. A better (and more scalable) way to do this would be to use the modulo operator (%) to ensure any number, no matter how large, would be able to yield a corresponding cipher text character. if new_index > 26: new_index %= 26 Rot N 13 is the most common value, as it allows for Symmetric Encryption. However, it's fairly simple to change this algorithm to accept any value for the rotation. To account for larger values, we need to change the index modification to the modulo style. Try it out! 123456789101112131415161718192021222324252627282930313233343536373839404142 def rot_n(plain_text, n): alphabet_dict = { 'a':1,'b':2,'c':3,'d':4,'e':5,'f':6,'g':7,'h':8,'i':9,'j':10 ,'k':11,'l':12,'m':13,'n':14,'o':15,'p':16,'q':17,'r':18 ,'s':19,'t':20,'u':21,'v':22,'w':23,'x':24,'y':25,'z':26 } number_dict = { 1:'a',2:'b',3:'c',4:'d',5:'e',6:'f',7:'g',8:'h',9:'i',10:'j' ,11:'k',12:'l',13:'m',14:'n',15:'o',16:'p',17:'q',18:'r' ,19:'s',20:'t',21:'u',22:'v',23:'w',24:'x',25:'y',26:'z' } cipher_text = "" new_index = 0 capitalized = False new_char = ' ' for char in plain_text: if char.isupper(): capitalized = True if char.lower() in alphabet_dict: new_index = int(alphabet_dict[char.lower()]) + n if new_index > 26: new_index %= 26 if new_index < 1: new_index %= 26 new_index += 26 if capitalized: cipher_text += number_dict[new_index].upper() else: cipher_text += number_dict[new_index] else: cipher_text += char capitalized = False return cipher_text print(rot_n("Uryyb jbeyq!@#$%^&*()_+-=/\\<>?,.~`", 14)) print(rot_n("Ifmmp xpsme!@#$%^&*()_+-=/\\<>?,.~`",-1)) print(rot_n("Hello world!@#$%^&*()_+-=/\\<>?,.~`",12)) print(rot_n("Tqxxa iadxp!@#$%^&*()_+-=/\\<>?,.~`",14)) Generate Character Messages via a Message Dictionary && Calculating a Message Code Say you want to cut down on the time taken with repetitive messages you want your game characters to say to the player. You could do this by using a dictionary to return a message based on an input value. Try it out! 12345678910111213141516171819 msg_dict = { 1:"Nice weather we're having!", 2:"Careful warrior...", 3:"Welcome to my blacksmith shop!", -1:"Watch it there...", "h_1":"Very spoooooky weather we're having!", "c_1":"Very frostie weather we're having!", "v_1":"Very bubbly weather we're having!", "eZ":"Hasta la vista, baby", "aB":"Groovy!" } def show_all_msg(): for num in msg_dict: print(msg_dict[num]) show_all_msg() You can also add the complexity of Holiday Based messages, Region Based messages, and many more! Try it out! 12345 def select_message_code(): return 0 12/13 Debugging ---------------------------------------------------------------------------------------------------------- Debugging One of the most frustrating things about learning a new coding language is the debugging. Debugging is the removal of flaws (bugs) in your code. There are a couple ways to categorize bugs. Syntax Errors The more obvious bugs are known as Syntax Errors. These happen whenever you misspell something or leave something out. Try to fix the code! 12345678910111213141516171819 print(Hello World") def test_func(n) print("test worked!") print(n) prnt(test_fun(10))) print(((test_func(10) my_int = 5 my_second_int = 10 print("My int is: " + my_int) # However, these seem to be ok... (no need for casting to str) print(my_int) print(my_int,my_second_int) Logic Errors Another type of bug is a Logic Error. These are harder to detect as they don't usually affect your code being able to run. These errors are more with your process for the task you're trying to do (aka algorithm). The first few lines show an index out of range error. This is pretty common in coding as the index usually starts at 0. Try to fix the code! 1234567891011121314 my_list = [1,2,3,4,5] print(my_list[10]) print(my_list[-10]) # Add the numbers 0-100 together and print the sum. my_sum = 0 for num in range(100): my_sum *= 5 print(my_sum) Notice that not only are you not finding the sum of all those numbers added together, you're also mulitplying by 0! Another thing to be aware of is PEMDAS (the order of operations in math). PEMDAS - Parenthesis Exponent Multiply Divide Add Subtract If you think that your bug is due to math not being done in the correct order, you can separate out pieces of your equation with parenthesis. Rubber Ducks An important concept in Computer Science is the Rubber Duck. Now, this can really be any inanimate object (or pet even), as long as it doesn't respond. The idea is to explain what your code is doing. Also, try explaining it different ways from different angles / points of view. Eventually, the hope is that you will discover the flaws / bugs in your code this way. In college, we used to bring real rubber ducks to the CS lab. Nowadays, I use a red octopus, or Roctopus! 13/13 Sorting Algorithms ---------------------------------------------------------------------------------------------------------- Sorting Algorithms A common problem in Computer Science is sorting data. Regardless of what data structure you're working with, you'll most likely want the ability to sort it in various ways. Sorting algorithms are also a very nice segway into Big O Complexity and Optimization concepts!