about the version field UPDATE1: In my memory, a lot of (maybe all?) collections in BCL have the field version. First, about foreach: according to this msdn link The foreach statement repeats a group of embedded statements for each element in an array or an object collection. The foreach statement is used to iterate through the collection to get … Read more
The theoretical answers from everyone else are all neat, but let’s be pragmatic. ActionScript provides the tools you need so that you don’t even have to write a loop in this case! First, note that Math.min() and Math.max() can take any number of arguments. Also, it’s important to understand the apply() method available to Function … Read more
It sounds like what you are asking for is an extention of the Halting Problem. I do not believe that such a thing is possible, even in theory. Just answering the question “Will this line of code ever run?” would be very difficult if not impossible to do in the general case. Edited to add: … Read more
Amortised time explained in simple terms: If you do an operation say a million times, you don’t really care about the worst-case or the best-case of that operation – what you care about is how much time is taken in total when you repeat the operation a million times. So it doesn’t matter if the … Read more
The answer depends on what exactly you mean by “regular expressions.” Classic regexes can be compiled into Deterministic Finite Automata that can match a string of length N in O(N) time. Certain extensions to the regex language change that for the worse. You may find the following document of interest: Regular Expression Matching Can Be … Read more
This is one of the most popular outlines: Regular Expression Matching Can Be Simple And Fast . Running a DFA-compiled regular expression against a string is indeed O(n), but can require up to O(2^m) construction time/space (where m = regular expression size).
It’s O(n). Consider this simple program: public class ArrayTest { public static void main(String[] args) { int[] var = new int[5]; } } The bytecode generated is: Compiled from “ArrayTest.java” public class ArrayTest extends java.lang.Object{ public ArrayTest(); Code: 0: aload_0 1: invokespecial #1; //Method java/lang/Object.”<init>”:()V 4: return public static void main(java.lang.String[]); Code: 0: iconst_5 1: … Read more
This follows easily from a simple fact in Calculus: and we have the following inequality: Here we can conclude that S = 1 + 1/2 + … + 1/n is both Ω(log(n)) and O(log(n)), thus it is Ɵ(log(n)), the bound is actually tight.
See Time Complexity. The python dict is a hashmap, its worst case is therefore O(n) if the hash function is bad and results in a lot of collisions. However that is a very rare case where every item added has the same hash and so is added to the same chain which for a major … Read more
Once expressed in big-O() notation, both are correct. However, during the derivation of the O() polynomial, in the case of binary search, only log2 is correct. I assume this distinction was the intuitive inspiration for your question to begin with. Also, as a matter of my opinion, writing O(log2 N) is better for your example, … Read more