Pascal’s Triangle with O(n^2) worst case.

public class PascalTriangle {
    
    public static void main(String[] args) {
        showPascal(9);
    }
    
    // This takes O(n^2) constraint.
    public static void showPascal(int rows){
    	// rows = Number of Pascal triangle rows to show up
    	// i = loop thru each row.
    	for(int i = 0; i<rows; i++)
    	{
    		// Start from 1. So, initialize the first number to 1
    		int number = 1;
    		// Give the spacing - Ex: If rows is 9, then the spacing  would 18 (because I specified the args as "", else if I specify args as "_", you would notice that the spacing is 17 and on 18th bit there would be a '_' ) for the first iteration of i = 0.
    		System.out.format("%"+(rows-i)*2+"s", "");
    		// j = loop thru  each column of a row by CALCULATing and display
    		for(int j=0; j<=i; j++)
    		{
    			// Give 3 more spacing and print the number on the 4th bit.
    			System.out.format("%4d", number);
    			
    			// Formula to calculate each column.
    			number = number * (i - j)/(j + 1);
    		}
    		// Print a empty line after each row.
    		System.out.println();
    	}
    }

Here is how the output look like:

Happy Coding !!!