Program to print diamond pattern using numbers and stars

Program to print the following pattern of a half diamond for N.

Example:

Input: N = 5
Output: 

1

2*3

4*5*6

7*8*9*10

11*12*13*14*15

11*12*13*14*15

7*8*9*10

4*5*6

2*3

1

This program is divided into four parts.

1
2*3
4*5*6
7*8*9*10
7*8*9*10
4*5*6
2*3
1

Time Complexity: O(N²) 
Auxiliary Space:  O(1) since we are not using any extra space