Example: Pascal's Triangle Generator in Java

// Pascal's Triangle Generator
import java.util.ArrayList;
import java.util.List;

// Main class containing the entry point of the program
public class Main {

    // LeetCode-style solution method
    public static List<List<Integer>> generate(int numRows) {
        List<List<Integer>> triangle = new ArrayList<>();

        if (numRows == 0) {
            return triangle;
        }

        // The first row is always [1]
        List<Integer> firstRow = new ArrayList<>();
        firstRow.add(1);
        triangle.add(firstRow);

        // Iterate from the second row up to numRows
        for (int i = 1; i < numRows; i++) {
            List<Integer> prevRow = triangle.get(i - 1); // Get the previous row
            List<Integer> currentRow = new ArrayList<>();

            // The first element of every row is always 1
            currentRow.add(1);

            // Calculate inner elements based on the previous row
            for (int j = 1; j < i; j++) {
                // Each element is the sum of the two elements directly above it
                currentRow.add(prevRow.get(j - 1) + prevRow.get(j));
            }

            // The last element of every row is always 1
            currentRow.add(1);

            // Add the newly formed row to the triangle
            triangle.add(currentRow);
        }

        return triangle;
    }

    public static void main(String[] args) {
        // Test cases
        System.out.println("Pascal's Triangle for numRows = 1:");
        System.out.println(generate(1)); // Expected: [[1]]
        System.out.println("\nPascal's Triangle for numRows = 3:");
        System.out.println(generate(3)); // Expected: [[1], [1, 1], [1, 2, 1]]
        System.out.println("\nPascal's Triangle for numRows = 5:");
        System.out.println(generate(5));
        /* Expected:
        [
             [1],
            [1,1],
           [1,2,1],
          [1,3,3,1],
         [1,4,6,4,1]
        ]
        */
    }
}