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The problem is to determine the number of unique transformations among a list of words when each letter in the word is transformed to a corresponding Morse code. Given a list of words, we want to find out how many different Morse code representations can be formed from these words.

Each letter in the English alphabet can be transformed into its corresponding Morse code using the following mapping:

'a' -> ".-"
'b' -> "-..."
'c' -> "-.-."
'd' -> "-.."
'e' -> "."
'f' -> "..-."
'g' -> "--."
'h' -> "...."
'i' -> ".."
'j' -> ".---"
'k' -> "-.-"
'l' -> ".-.."
'm' -> "--"
'n' -> "-."
'o' -> "---"
'p' -> ".--."
'q' -> "--.-"
'r' -> ".-."
's' -> "..."
't' -> "-"
'u' -> "..-"
'v' -> "...-"
'w' -> ".--"
'x' -> "-..-"
'y' -> "-.--"
'z' -> "--.."

Given a list of words, return the number of different transformations among all words.

Clarifying Questions

1. Input Constraints:
   • Are there any constraints on the length of the words list or the length of any individual word?
   • Should we consider case sensitivity, or can we assume all words are in lowercase?
2. Output Format:
   • Should the unique transformations be returned as well, or just the count?

Strategy

1. Convert Each Word to Morse Code:
   • We will use the provided mapping to convert each letter in a word to its corresponding Morse code.
2. Store Transformations:
   • Use a set to store unique Morse code transformations since sets automatically handle duplicates.
3. Return the Size of the Set:
   • The size of the set will give us the number of different Morse code representations.

Pseudocode

1. Create a list of Morse code strings corresponding to each letter a-z.
2. Initialize an empty set to store unique Morse code representations.
3. Iterate over each word in the given list.
4. For each word, iterate over its characters and build the Morse code transformation.
5. Add the transformation to the set.
6. Return the size of the set.

Code

def uniqueMorseRepresentations(words):
    morse_code_map = [".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..", 
                      ".---", "-.-", ".-..", "--", "-.", "---", ".--.", "--.-", ".-.", 
                      "...", "-", "..-", "...-", ".--", "-..-", "-.--", "--.."]
    
    transformations = set()  # Using a set to store unique transformations
    
    for word in words:
        transformation = ''.join(morse_code_map[ord(char) - ord('a')] for char in word)
        transformations.add(transformation)
    
    return len(transformations)

# Example usage:
words = ["gin", "zen", "gig", "msg"]
print(uniqueMorseRepresentations(words))  # Output: 2

Time Complexity

• The time complexity of this solution is (O(n \times m)), where (n) is the number of words, and (m) is the average length of the words.
• Each word is processed to create its Morse code transformation, and since the operations (joining characters) and setting operations (adding to a set) are efficient, this complexity is acceptable for most realistic inputs.

Edge Cases and Considerations

• All words being identical: The function should correctly identify just one unique transformation.
• No words in the input list: Should return 0.
• Words containing all unique characters: Should correctly compute each distinct transformation.

Feel free to ask any further clarifications or questions!

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