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Naive Pattern Search

Visualize finding all occurrences of a pattern in a text by checking every position.

Ready to search for pattern.
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C
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D
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Matches Found

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Intuition

Slide the pattern over the text one by one and check for a match. If a match is found, record the index. If a mismatch occurs, shift the pattern by one position.

Concept

  • Sliding Window: The pattern acts as a window of length M.
  • Comparison: Compare character by character.
  • Shift: Move window by 1 after every check.

How it Works

Algorithm:

  1. Loop i from 0 to N - M.
  2. For each i, loop j from 0 to M - 1.
  3. If text[i+j] != pattern[j], break inner loop.
  4. If inner loop completes (j == M), pattern found at i.

Step-by-Step Breakdown

Watch the visualization:

  • The dashed box represents the pattern.
  • It moves one step at a time.
  • Green border = Match, Red border = Mismatch.

When to Use

  • Small texts or patterns.
  • When simplicity is preferred over performance.

When NOT to Use

  • Large texts (O(N*M) is too slow). Use KMP or Rabin-Karp instead.

How to Identify

"Find occurrence of pattern", "Substring search".

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