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Day 56

Day 56: String Algorithms - KMP

56/60 Days

Day 56: String Algorithms - Knuth-Morris-Pratt (KMP) #

Welcome to Day 56 of our 60 Days of Coding Algorithm Challenge! Today, we’ll explore the Knuth-Morris-Pratt (KMP) algorithm, an efficient string matching algorithm that improves upon the naive approach for finding a pattern within a text.

What is the KMP Algorithm? #

The Knuth-Morris-Pratt (KMP) algorithm is a string matching algorithm that searches for occurrences of a “word” W within a main “text string” S by employing the observation that when a mismatch occurs, the word itself embodies sufficient information to determine where the next match could begin, thus bypassing re-examination of previously matched characters.

How KMP Works #

The key idea behind KMP is to utilize the information gained by previous match attempts to skip redundant comparisons. It does this by pre-processing the pattern to create a “failure function” or “partial match table” that is used to skip characters in the input string.

The algorithm consists of two main steps:

  1. Preprocessing: Create the failure function for the pattern.
  2. Searching: Use the failure function to perform the …