"""
-------------------------------------------------------------------------
What is a trigram?
-------------------------------------------------------------------------
A trigram is a sequence of exactly three consecutive characters taken
from a word. To generate all trigrams, we slide a window of length 3
across the string. Each step produces a new 3‑character slice.
Example:
Word: "magic"
Trigrams: ["mag", "agi", "gic"]
Trigrams are useful in text processing, search algorithms,
and language modeling because they capture small structural patterns
inside words.
"""
def make_trigrams(word: str) -> list[str]:
"""
Return all trigrams (3‑character sequences) from the given word.
Steps:
- If the word is shorter than 3 characters, return an empty list.
- Otherwise, slide a window of size 3 across the word.
- Use slicing to extract each 3‑character sequence.
The algorithm runs in O(n) time and uses O(n) space.
"""
if len(word) < 3:
return []
count = len(word) - 2
return [word[i:i+3] for i in range(count)]
def main():
"""
Main program:
- Read a word from the user.
- Generate trigrams.
- Print each trigram.
"""
word = input("Enter a word: ").strip()
trigrams = make_trigrams(word)
print("\nTrigrams:")
for t in trigrams:
print(t)
if __name__ == "__main__":
main()
"""
run:
Enter a word: computer
Trigrams:
com
omp
mpu
put
ute
ter
"""
