Menu
Possible Duplicate:
What is the cost / complexity of a String.indexof() function call
What is the complexity of java indexof(String str) method. I mean there are String matching algorithms like KMP which runs in linear time. I am implementing a system that needs to search for large substring in a really large string,so can I use java indexof(String str) method or I should to implement KMP.
221
indexOf() – also runs in linear time. It iterates through the internal array and checks each element one by one, so the time complexity for this operation always requires O(n) time.
The complexity of Java's implementation of indexOf is O(m*n) where n and m are the length of the search string and pattern respectively.
Even if I switch the order of indexOf and contains, indexOf is still faster. In the benchmark i linked, the passed value is also alreday a string!
The indexOf() method returns the position of the first occurrence of substring in string. The first position in the string is 0. If the indexOf() method does not find the substring in string, it will return -1.
The complexity of Java's implementation of indexOf is O(m*n) where n and m are the length of the search string and pattern respectively.
What you can do to improve complexity is to use e.g., the Boyer-More algorithm to intelligently skip comparing logical parts of the string which cannot match the pattern.
162
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
