Quick Reference Tools
Big O Cheat Sheet
| O(1) |
Constant |
Excellent |
| O(log n) |
Logarithmic |
Great |
| O(n) |
Linear |
Good |
| O(n log n) |
Linearithmic |
Fair |
| O(n²) |
Quadratic |
Poor |
| O(2^n) |
Exponential |
Terrible |
HTTP Status Codes
| 200 |
OK |
| 201 |
Created |
| 301 |
Moved Permanently |
| 400 |
Bad Request |
| 401 |
Unauthorized |
| 403 |
Forbidden |
| 404 |
Not Found |
| 500 |
Internal Server Error |
Common Regex Patterns
\d+ |
One or more digits |
\w+ |
Word characters |
[a-zA-Z] |
Letters only |
^...$ |
Full string match |
.*? |
Non-greedy any |
(?:...) |
Non-capture group |
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