Hollow Pyramid

Given an integer N, print a hollow pyramid of N rows. The perimeter lines (first row apex, bottom row base, left edge, and right edge) contain stars (*), while the interior contains spaces.

Input Format

A single integer N.

Output Format

Print N rows forming a hollow pyramid.

Constraints:1 <= N <= 20

Concepts Required:

Interior hollow spacingBase edge boundary checkCentered triangular geometry

Expected Pattern PreviewASCII Monospace

    *
   * *
  *   *
 *     *
*********

Notice how character spacing and row counts scale systematically based on the input N.

Concrete Examples

Example 1

Input:

Output:

    *
   * *
  *   *
 *     *
*********

Explanation: Row 1 has 1 star. Rows 2-4 have 2 stars separated by spaces. Row 5 is completely filled with 9 stars.

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