binary-search

Simple question - given an IList<T> how do you perform a binary search without writing the method yourself and without copying the data to a type with build-in binary search support. My current status is the following. List<T>.BinarySearch() is not a member of IList<T> There is no equivalent of the ArrayList.Adapter() method for List<T> IList<T> does not inherit from IList , hence using ArrayList.Adapter() is not possible I tend to believe that is not possible with build-in methods, but I cannot believe that such a basic method is missing from the BCL/FCL. If it is not possible, who can give

Is there any way to implement binary search in a ArrayList with objects? In this example the ArrayList will be sorted with the field 'id'. class User{ public int id; public string name; } ArrayList<User> users = new ArrayList<User>(); sortById(users); int id = 66 User searchuser = getUserById(users,id); How would the "User getUserById( ArrayList users, int userid )" look like if I it should return the user with a specified id using binary search? Is this even possible? The Object Ordering article of The Java Tutorials has an example of writing your own Comparator in order to perform

I heard somebody say that since binary search halves the input required to search hence it is log(n) algorithm. Since I am not from a mathematics background I am not able to relate to it. Can somebody explain it in a little more detail? does it have to do something with the logarithmic series? duedl0r Here a more mathematical way of seeing it, though not really complicated. IMO much clearer as informal ones: The question is, how many times can you divide N by 2 until you have 1? This is essentially saying, do a binary search (half the elements) until you found it. In a formula this would be