Question

I have came with solution to remove duplicates from generic list<T> in .NET 2.0 as follows:

List<CaseStudy> caseStudies = CaseStudyDAO.FindCaseStudiesByDate(DateTime.Now.Date, DateTime.Now.Date.AddDays(1));
caseStudies.RemoveAll(
        delegate(CaseStudy c)
        {
            return caseStudies.IndexOf(c) != caseStudies.FindIndex(
                delegate(CaseStudy f) { return c.Str == f.Str; });
        });

My questions are:

Is there more efficient way to do this? Only .NET 2.0 solution
What is the complexity of the above solution?

Thanks,
jan2k10

Answer 1

The time complexity of RemoveAll is O(n). The time complexity of the indexing is O(n), so that’s a grand total of O(n^2) time complexity. The space complexity is, I think, O(1).

Is there a more efficient way to do it? Yes. You can do it in O(n) time complexity provided you’re willing to spend more space on it.