How to identify the maximum number of overlapping date ranges?

问题

This question might be similar to:

Determine Whether Two Date Ranges Overlap
Multiple Date range comparison for overlap: how to do it efficiently?

But, how can I get the maximum number of overlapping date ranges? (preferably in C#)

Example: (from - to)

01/01/2012 - 10/01/2012
03/01/2012 - 08/01/2012
09/01/2012 - 15/01/2012
11/01/2012 - 20/01/2012
12/01/2012 - 14/01/2012

Result = 3 maximum overlapping date ranges

Solution: Possible implementation of the solution proposed by @AakashM

List<Tuple<DateTime, int>> myTupleList = new List<Tuple<DateTime, int>>();

foreach (DataRow row in objDS.Tables[0].Rows) // objDS is a DataSet with the date ranges
{
    var myTupleFrom = new Tuple<DateTime, int>(DateTime.Parse(row["start_time"].ToString()), 1);
    var myTupleTo = new Tuple<DateTime, int>(DateTime.Parse(row["stop_time"].ToString()), -1);
    myTupleList.Add(myTupleFrom);
    myTupleList.Add(myTupleTo);
}

myTupleList.Sort();

int maxConcurrentCalls = 0;
int concurrentCalls = 0;
foreach (Tuple<DateTime,int> myTuple in myTupleList)
{
    if (myTuple.Item2 == 1)
    {
        concurrentCalls++;
        if (concurrentCalls > maxConcurrentCalls)
        {
            maxConcurrentCalls = concurrentCalls;
        }
    }
    else // == -1
    {
        concurrentCalls--;
    }
}

Where maxConcurrentCalls will be the maximum number of concurrent date ranges.

回答1:

For each range, create two Tuple<DateTime, int>s with values start, +1 and end, -1
Sort the collection of tuples by date
Iterate through the sorted list, adding the number part of the tuple to a running total, and keeping track of the maximum value reached by the running total
Return the maximum value the running total reaches

Executes in O(n log n) because of the sort. There's probably a more efficient way.

来源：https://stackoverflow.com/questions/11956589/how-to-identify-the-maximum-number-of-overlapping-date-ranges

标签

date

date-range