How to know whether there is any overlap in a collection of periods using LINQ

Question

I have a collection of periods [FromDate, ToDate].

I would know whether there is any overlap between a given period and the periods in the collection.

Answer 1

Do 2 periods having common date, say ToDate for period 1 and FromDate of period 2 are the same, count as in intersection ?

If yes then a little modification to your query to simply check the dates of a period if are within the checked period separately as if one of the dates falls inside a period then there is intersection:

bool conflict = Periods.Any(p => ((p.FromDate >= periodToCheck.fromDate && 
                                    p.ToDate <= periodToCheck.fromDate)
                                  ||
                                   (p.FromDate >= periodToCheck.toDate && 
                                    p.ToDate <= periodToCheck.toDate))
                             );