Welcome to this insightful lesson on string searching algorithms, a core part of programming often used in software development, database design, and information retrieval. Today, we’ll introduce you to one of the most efficient approaches — the Knuth-Morris-Pratt (KMP) algorithm.
The KMP algorithm optimizes string searching by avoiding unnecessary backtracking. Rather than re-checking characters in the text, it uses a precomputed array called the Longest Prefix Suffix (LPS) array to skip over parts that have already been matched. Here’s the code:
Here's what's happening in the above code:
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The
compute_lpsfunction builds the Longest Prefix Suffix (LPS) array for thepattern, helping determine skips in case of mismatches. For each character, if it matches the previous prefix,lengthis incremented; otherwise, it resets to avoid redundant checks. -
The main function then uses this array to match characters in
patternandtext. On mismatches, it leverageslpsto skip parts of the pattern, avoiding unnecessary comparisons.
Ready to deepen your understanding? We’ll dive into hands-on exercises to solidify your grasp of these concepts and help you see how these algorithms can be applied in real-world programming tasks. Remember, mastering the "why" behind each step will set you up for success in tackling complex problems!
