Crawl budget optimization in SEO Fundamentals - Time & Space Complexity

Time Complexity: Crawl budget optimization

O(n)

Understanding Time Complexity

When search engines visit a website, they have a limited amount of time and resources to explore its pages. This limit is called the crawl budget.

We want to understand how the number of pages affects the time it takes for search engines to crawl a site.

Scenario Under Consideration

Analyze the time complexity of this simplified crawl process:

for each page in website:
  if page is allowed to be crawled:
    fetch page content
    extract links
    add new links to crawl list

This code simulates how a search engine visits pages, checks if it can crawl them, and finds new pages to visit.

Identify Repeating Operations

Look at what repeats as the crawl runs:

• Primary operation: Visiting each allowed page and extracting links.
• How many times: Once per page that is allowed and discovered.

How Execution Grows With Input

As the number of pages grows, the crawler visits more pages and extracts more links.

Input Size (n)	Approx. Operations
10	About 10 page visits and link extractions
100	About 100 page visits and link extractions
1000	About 1000 page visits and link extractions

Pattern observation: The work grows roughly in direct proportion to the number of pages crawled.

Final Time Complexity

Time Complexity: O(n)

This means the time to crawl grows linearly with the number of pages allowed and discovered.

Common Mistake

[X] Wrong: "Crawling time stays the same no matter how many pages there are."

[OK] Correct: More pages mean more visits and link checks, so crawling takes longer as the site grows.

Interview Connect

Understanding crawl budget helps you think about how systems handle growing data efficiently, a useful skill in many tech roles.

Self-Check

What if the crawler skips pages blocked by robots.txt early? How would that affect the time complexity?