The BF (Boyer-Moore) algorithm is a string matching algorithm, which is a fast pattern matching algorithm. Its basic idea is to reduce the number of matches by preprocessing the information in the pattern string. When it looks for pattern strings in text strings, it uses bad character rules and good suffix rules to move pattern strings to improve matching efficiency.
BF (Brute Force) algorithm is a violent enumeration algorithm, usually used to find the target value in a sequence. Here is an example of a simple BF algorithm for finding the position of a substring in a string:
def find_substring(s, target):
n = len(s)
m = len(target)
for i in range(n - m + 1):
j = 0
while j < m and s[i + j] == target[j]:
j += 1
if j == m:
return i
return -1
This algorithm finds the position of the target string target in s by enumerating all substrings of length m in string s and comparing them character by character. Returns the starting position of the target string in s if found, or -1 if not found.
Note that the time complexity of this algorithm is O(n * m), so it may be slow for large n and m.
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