c# implementation get range of values and union of these ranges

I have a situation that is well explained 开发者_StackOverflow中文版in this question:

Range intersection / union

I need a C# implementation (a collection maybe) that takes a list of ranges (of ints) and do the union of them. Then I need to iterate through all ints in this collection (also numbers between ranges) Are there any library/implementation so that I don't have to rewrite everything by myself?

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You might take a look at this implementation and see if it will fit your needs.

Combine ranges with Range.Coalesce:

var range1 = Range.Create(0, 5, "Range 1");
var range2 = Range.Create(11, 41, "Range 2");
var range3 = Range.Create(34, 50, "Range 3");
var ranges = new List<Range> { range1, range2, range3 };
var unioned = Range.Coalesce(ranges);

Iterate over ranges with .Iterate:

foreach (var range in unioned)
{
    foreach (int i in range.Iterate(x => x + 1))
    {
        Debug.WriteLine(i);
    }
}

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The simplest thing that comes to my mind is to use Enumerable.Range, and then treat the different IEnumerable with standard linq operators. Something like:

var list = Enumerable.Range(1, 5)
.Concat(Enumerable.Range(7, 11))
.Concat(Enumerable.Range(13, 22))

foreach(var number in list)
  // Do something

Obviously you can use Union and Intersect as well... clearly you can also put your ranges in a List<IEnumerable<int>> or something similar and then iterate over the elements for producing a single list of the elements:

var ranges = new List<IEnumerable<int>> 
{ 
    Enumerable.Range(1, 5), 
    Enumerable.Range(7, 11), 
    Enumerable.Range(10, 22) 
};
var unionOfRanges = Enumerable.Empty<int>();

foreach(var range in ranges)
    unionOfRanges = unionOfRanges.Union(range);

foreach(var item in unionOfRanges)
    // Do something

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The following is vanilla Linq implementation:

var r1 = Enumerable.Range(1,10);
var r2 = Enumerable.Range(20,5);
var r3 = Enumerable.Range(-5,10);

var union = r1.Union(r2).Union(r3).Distinct();

foreach(var n in union.OrderBy(n=>n))
    Console.WriteLine(n);

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System.Collections.Generic.HashSet has just the thing:

• UnionWith( IEnumerable<T> other ). Modifies the current HashSet object to contain all elements that are present in itself, the specified collection, or both.
• IntersectWith( IEnumerable<T> other ). Modifies the current HashSet object to contain only elements that are present in that object and in the specified collection.

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The data structure you are looking for is called an "interval tree".

You can find different implementations on the net.

For example here's one: http://www.emilstefanov.net/Projects/RangeSearchTree.aspx