import java.util.Scanner;
/**
-------------------------------------------------------------------------
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.
*/
public class TrigramGenerator {
/**
Function: makeTrigrams
----------------------
Returns an array containing all trigrams of the given word.
Steps:
- If the word is shorter than 3 characters, return an empty array.
- Otherwise, slide a window of size 3 across the word.
- Use substring() to extract each 3‑character sequence.
The algorithm is efficient: O(n) time, O(n) space.
*/
public static String[] makeTrigrams(String word) {
if (word.length() < 3) {
return new String[0]; // No trigrams possible
}
int count = word.length() - 2;
String[] result = new String[count];
for (int i = 0; i < count; i++) {
result[i] = word.substring(i, i + 3);
}
return result;
}
/**
Main program:
- Read a word from the user.
- Generate trigrams.
- Print each trigram.
*/
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter a word: ");
String input = scanner.nextLine();
String[] trigrams = makeTrigrams(input);
System.out.println("\nTrigrams:");
for (String t : trigrams) {
System.out.println(t);
}
scanner.close();
}
}
/*
run:
Enter a word: computer
Trigrams:
com
omp
mpu
put
ute
ter
*/
