Goat Latin

Let’s walk through this step by step:

  1. Split the sentence into words.

  2. For each word, check if it starts with a vowel. If it does, append “ma” to the end of the word. If it does not, remove the first character, append it to the end of the word, then add “ma”.

  3. Next, according to its index in the original sentence, append ‘a’ repeated i + 1 times to each word. Here, i is the index of the word in the sentence (starting from 0).

  4. Join the words back together into a sentence and return.

Python solution:

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class Solution:
    def toGoatLatin(self, sentence: str) -> str:
        words = sentence.split()
        vowels = {'a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U'}
        for i in range(len(words)):
            if words[i][0] in vowels:
                words[i] += 'ma'
            else:
                words[i] = words[i][1:] + words[i][0] + 'ma'
            words[i] += 'a' * (i + 1)
        return ' '.join(words)

In this code, we start by splitting the sentence into words. We then iterate through each word and modify it according to the rules. The vowels set is used to check if the first letter of a word is a vowel. We then add ‘a’ repeated i + 1 times to the end of the word, where i is the index of the word in the sentence. Finally, we join the modified words back into a sentence with ’ ‘.join(words) and return it.

Identifying Problem Isomorphism

“Goat Latin” involves string manipulation, following a set of rules to transform an input string into the Goat Latin language.

A simpler problem that involves string manipulation is “Reverse Words in a String III”. In this problem, you are required to reverse each word in a string, which is a subset of the operations required in “Goat Latin”.

An approximate isomorphic problem is “Decode String”. This problem involves similar operations of manipulating a string based on a set of rules. However, it involves stack operations to decode a string, which might be a bit more complex.

A more complex problem is “Basic Calculator II”. This problem involves not only string manipulation but also calculation based on the operators in the string.

Therefore, from simplest to more complex:

  1. “Reverse Words in a String III” - Reverse each word in a string.
  2. “Goat Latin” - Follow a set of rules to transform an input string into the Goat Latin language.
  3. “Decode String” - Follow the rules to decode a string that contains digits and brackets.
  4. “Basic Calculator II” - Implement a basic calculator to evaluate a string expression containing non-negative integers and ‘+’, ‘-’, ‘*’, ‘/’ operators.
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class Solution:
    def toGoatLatin(self, S):
        words = S.split()
        vowels = set("AEIOUaeiou")
        for i in range(len(words)):
            if words[i][0] in vowels:
                words[i] = words[i] + "ma" + "a"*(i+1)
            else:
                words[i] = words[i][1:] + words[i][0] + "ma" + "a"*(i+1)

        return " ".join(words)

Problem Classification

This problem falls primarily into the domain of “String Manipulation”. It involves the application of specific transformation rules on words in a sentence, which requires understanding and implementing string and list operations.

The “What” components of this problem are:

  1. A sentence consisting of words separated by spaces.
  2. Each word in the sentence consists of lowercase and uppercase letters only.
  3. Transformation rules based on the starting character of each word (vowel or consonant) and the word’s position in the sentence.
  4. The final goal is to return a new sentence with all words transformed according to these rules.

Further classification of this problem could involve:

  1. Text Processing: The problem involves manipulating and transforming strings, which is a key aspect of text processing.
  2. Rule-Based Systems: The transformations are determined by a set of explicit rules.
  3. Algorithmic Thinking: Implementing the transformation process involves designing an algorithm to iterate over the sentence, apply the correct rule for each word, and assemble the result.

The problem requires understanding of string operations, conditional logic, loops, and list manipulation, making it a good exercise for learning and practicing these fundamental coding concepts.

Language Agnostic Coding Drills

  1. Concept Identification

The given code makes use of a few core concepts:

a) **Defining and using a class and method**: The outermost layer of the program structure is a class, inside which a method is defined and used.

b) **String operations**: Several string operations are utilized, including string splitting (`split()`), concatenation (`+`), indexing, and repetition (`*`).

c) **Control Structures**: The code uses a loop (specifically, a `for` loop) and an `if`-`else` conditional statement.

d) **Set creation and membership testing**: A set of vowels is created, and the membership of an element in this set is tested.

e) **Working with lists**: The code manipulates lists, including iterating through a list and modifying its elements.

f) **Conversion between list and string**: The `join()` function is used to convert a list of strings back into a single string.

  1. Concept Difficulty Ordering

    a) Defining and using a class and method: This is a basic concept of object-oriented programming.

    b) String operations: String manipulation is also a fundamental concept in Python and most other programming languages.

    c) Control Structures: Conditional statements and loops are common and essential in most programming tasks, though they can take some practice to use effectively.

    d) Set creation and membership testing: Creating a set and checking for membership are relatively straightforward but can be unfamiliar to those new to Python or programming in general.

    e) Working with lists: List manipulation is an essential part of Python and many other languages, but it can become complex when it involves modifying elements in place.

    f) Conversion between list and string: The use of join() is simple once understood, but initially grasping the concept of converting a list to a string can be a bit tricky for beginners.

  2. Problem-Solving Approach

The problem can be solved by following a series of steps:

a) Start by splitting the sentence into words using the split() function.

b) Create a set of vowels for easy and efficient membership testing.

c) Loop through each word in the sentence. For each word, check if the first character is a vowel. If it is, append “ma” and then “a” repeated for the 1-indexed position in the sentence. If it’s not a vowel, remove the first character, append it to the end, and then append “ma” and the repeated “a"s.

d) Finally, join all the transformed words back into a sentence using the join() function.

Each of the identified concepts or drills corresponds to one or more of these steps. By understanding and mastering each of these concepts, a learner can then apply them in the right sequence to implement the solution to the problem.

Targeted Drills in Python

  1. Python-based coding drills for each identified concept

    a) Defining and using a class and method:

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    class ExampleClass:
    def example_method(self):
        print("This is an example method")

my_instance = ExampleClass()
my_instance.example_method()

    b) String operations:

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    string = "hello"
print(string + " world")  # Concatenation
print(string * 3)  # Repetition
print(string[1])  # Indexing

    c) Control Structures:

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    for i in range(5):  # Loop
    if i % 2 == 0:  # Conditional
        print(i, "is even")
    else:
        print(i, "is odd")

    d) Set creation and membership testing:

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    my_set = set(['a', 'b', 'c'])
print('a' in my_set)
print('d' in my_set)

    e) Working with lists:

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    my_list = [1, 2, 3, 4, 5]
for i in range(len(my_list)):
    my_list[i] = my_list[i] ** 2
print(my_list)

    f) Conversion between list and string:

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    my_list = ['This', 'is', 'a', 'sentence.']
my_string = " ".join(my_list)
print(my_string)

  2. Problem-specific concepts

The problem-specific concept here is the transformation of each word according to the Goat Latin rules. A drill that encapsulates this concept might look like:

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word = 'goat'
vowels = set('aeiouAEIOU')
if word[0] in vowels:
    new_word = word + 'ma' + 'a'*2
else:
    new_word = word[1:] + word[0] + 'ma' + 'a'*2
print(new_word)

This drill is essential as it directly demonstrates the specific transformations required by the problem statement.

  1. Integration of Drills

With all these drills prepared, we can integrate them together as follows:

a) Start by defining a class and method structure. Inside the method, begin with splitting the input sentence into words (string operations drill).

b) Create a set of vowels (set creation and membership testing drill).

c) Initialize a loop to go through each word (control structures drill). Inside the loop, transform each word according to whether it starts with a vowel or a consonant, and append the appropriate number of ‘a’s at the end (problem-specific drill and string operations drill).

d) Modify the words list in place to hold the transformed words (working with lists drill).

e) Finally, join the transformed words back together into a sentence (conversion between list and string drill), and return this as the result.