Python Program to Print Pyramid Pattern

You can print a pyramid pattern in Python using nested loops like for i in range(1, n+1): print(' '*(n-i) + '*'*(2*i-1)) where n is the number of pyramid levels.

Examples

Input3

Output * *** *****

Input5

Output * *** ***** ******* *********

Input1

Output*

How to Think About It

To print a pyramid pattern, think of each line as having spaces followed by stars. The number of spaces decreases each line, and the number of stars increases by two. Use one loop to go through each line and inside it, print spaces first, then stars.

Algorithm

1

Get the number of levels (n) for the pyramid.

2

For each line from 1 to n:

3

Calculate and print spaces equal to (n - current line number).

4

Calculate and print stars equal to (2 * current line number - 1).

5

Move to the next line.

Code

python

n = int(input('Enter number of levels: '))
for i in range(1, n + 1):
    print(' ' * (n - i) + '*' * (2 * i - 1))

Output

Enter number of levels: 5
    *
   ***
  *****
 *******
*********

Dry Run

Let's trace the pyramid pattern for n=3 through the code

1

Input

n = 3

2

First line (i=1)

spaces = 3 - 1 = 2, stars = 2*1 - 1 = 1, print ' *'

3

Second line (i=2)

spaces = 3 - 2 = 1, stars = 2*2 - 1 = 3, print ' ***'

4

Third line (i=3)

spaces = 3 - 3 = 0, stars = 2*3 - 1 = 5, print '*****'

i	spaces	stars	line output
1	2	1	*
2	1	3	***
3	0	5	*****

Why This Works

Step 1: Spaces decrease each line

We print n - i spaces to push stars to the right, creating the pyramid shape.

Step 2: Stars increase by two

We print 2 * i - 1 stars to form the pyramid's width, growing by two each line.

Step 3: Loop controls lines

The outer loop runs from 1 to n, controlling how many lines the pyramid has.

Alternative Approaches

Using while loops

python

n = int(input('Enter levels: '))
i = 1
while i <= n:
    print(' ' * (n - i) + '*' * (2 * i - 1))
    i += 1

This uses while loops instead of for loops; functionally the same but less concise.

Using string center method

python

n = int(input('Enter levels: '))
for i in range(1, n + 1):
    print(('*' * (2 * i - 1)).center(2 * n - 1))

This centers the stars automatically, making code cleaner and easier to read.

Complexity: O(n^2) time, O(1) space

Time Complexity

The program uses nested printing for each line, with the number of stars and spaces growing linearly, resulting in O(n^2) time.

Space Complexity

Only a few variables are used, and printing is done directly, so space complexity is O(1).

Which Approach is Fastest?

All approaches have similar time complexity; using string center method improves readability but not speed.

Approach	Time	Space	Best For
For loops with manual spaces	O(n^2)	O(1)	Clear control over spaces and stars
While loops	O(n^2)	O(1)	Beginners learning loop basics
String center method	O(n^2)	O(1)	Cleaner code and readability