Pattern Programs in Python

A collection of 22 foundational pattern printing algorithms implemented in Python, designed to build loop mastery, nested iteration control, and spatial logic for technical interviews.

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Overview

Pattern printing problems serve as a fundamental building block in computer science education. Mastering these exercises develops:

• Precise control over multi-dimensional loops and loop bounds
• Mathematical mapping between indices and printable output
• Spatial visualization essential for matrix operations, dynamic programming tables, and recursion trees
• Time and space complexity awareness in nested iterations

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Pattern Catalog

#	Pattern Name	Difficulty	Folder	Source Code
01	Rectangular Star Pattern	Easy	01/	one.py
02	Right-Angled Triangle (Stars)	Easy	02/	two.py
03	Right-Angled Number Pyramid	Easy	03/	three.py
04	Right-Angled Number Pyramid - II	Easy	04/	four.py
05	Inverted Right Pyramid (Stars)	Easy	05/	five.py
06	Inverted Numbered Right Pyramid	Easy	06/	six.py
07	Star Pyramid	Easy	07/	seven.py
08	Inverted Star Pyramid	Easy	08/	eight.py
09	Diamond Star Pattern	Medium	09/	nine.py
10	Half Diamond Star Pattern	Easy	10/	ten.py
11	Binary Number Triangle	Easy	11/	eleven.py
12	Number Crown Pattern	Medium	12/	twelve.py
13	Increasing Number Triangle (Floyd's Triangle)	Easy	13/	thirteen.py
14	Increasing Letter Triangle	Easy	14/	fourteen.py
15	Reverse Letter Triangle	Easy	15/	fifteen.py
16	Alpha-Ramp Pattern	Easy	16/	sixteen.py
17	Alpha-Hill Pattern	Medium	17/	seventeen.py
18	Alpha-Triangle Pattern	Medium	18/	eighteen.py
19	Symmetric Void Pattern	Medium	19/	nineteen.py
20	Symmetric Butterfly Pattern	Medium	20/	twenty.py
21	Hollow Rectangle Pattern	Medium	21/	twentyone.py
22	The Number Pattern (Concentric Square)	Hard	22/	twentytwo.py

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Pattern Solving Framework

Every pattern problem can be decomposed into four standard algorithmic steps:

1. Row Count Determination (Outer Loop): Identify the total number of lines to print, establishing the outer loop range (i from 0 to rows - 1).
2. Horizontal Offsets / Spacing (Inner Loop 1): Calculate leading whitespace or central gap formulas as a function of row index i and input dimension N.
3. Symbol / Value Mapping (Inner Loop 2): Determine the number of printed characters, numbers, or alphabetic values per row, along with any increment/decrement rules.
4. Row Termination: Print a newline after all row elements are emitted to advance the cursor.

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Execution

Requirements

• Python 3.8 or higher

Running Solutions

Execute any pattern by navigating to the repository root and running the corresponding script:

# Pattern 01: Rectangular Star Pattern
python 01/one.py

# Pattern 07: Star Pyramid
python 07/seven.py

# Pattern 12: Number Crown Pattern
python 12/twelve.py

# Pattern 22: Concentric Number Pattern
python 22/twentytwo.py

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Repository Structure

patterns/
├── 01/
│   ├── README.md
│   ├── one.png
│   └── one.py
├── 02/
│   ├── README.md
│   ├── two.png
│   └── two.py
...#all folders==all patterns
├── 22/
│   ├── README.md
│   ├── twentytwo.png
│   └── twentytwo.py
└── README.md

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License

This project is licensed under the MIT License - see the LICENSE file for details.