Complexity Analysis of Naive algorithm for Pattern Searching
Best Case: O(n)
- When the pattern is found at the very beginning of the text (or very early on).
- The algorithm will perform a constant number of comparisons, typically on the order of O(n) comparisons, where n is the length of the pattern.
Worst Case: O(n2)
- When the pattern doesn’t appear in the text at all or appears only at the very end.
- The algorithm will perform O((n-m+1)*m) comparisons, where n is the length of the text and m is the length of the pattern.
- In the worst case, for each position in the text, the algorithm may need to compare the entire pattern against the text.
- Naive algorithm for Pattern Searching
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PHP Program for Naive algorithm for Pattern Searching
Write a PHP program for a given text string with length n and a pattern with length m, the task is to print all occurrences of the pattern in text.
Note: You may assume that n > m.
Examples:
Input: text = “THIS IS A TEST TEXT”, pattern = “TEST”
Output: Pattern found at index 10Input: text = “AABAACAADAABAABA”, pattern = “AABA”
Output: Pattern found at index 0, Pattern found at index 9, Pattern found at index 12