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  1. using System;
  2. using System.Linq;
  3. using System.Collections.Generic;
  4.  
  5. public class Test
  6. {
  7.        class Range
  8.         {
  9.             public int? Start { get; set; }
  10.             public int? End { get; set; }
  11.         }
  12.  
  13.         private static IEnumerable<Range> getAdjacentRanges(IEnumerable<int> nums)
  14.         {
  15.             var ranges = new List<Range>();
  16.             if (!nums.Any())
  17.                 return ranges;
  18.  
  19.             var ordered = nums.OrderBy(i => i);
  20.             int lowest = ordered.First();
  21.             ranges.Add(new Range { Start = lowest });
  22.             int last = lowest;
  23.             Range lastRange = null;
  24.  
  25.             foreach (int current in ordered)
  26.             {
  27.                 lastRange = ranges[ranges.Count - 1];
  28.                 if (current > last + 1)
  29.                 {
  30.                     lastRange.End = last;
  31.                     ranges.Add(new Range { Start = current });
  32.                 }
  33.                 last = current;
  34.             }
  35.  
  36.             return ranges;
  37.         }
  38.  
  39. 	public static void Main()
  40. 	{
  41. 	        var arr = new[] { 1, 2, 3, 4, 8, 9, 10, 15 };
  42.             var ranges = getAdjacentRanges(arr)
  43.                 .Select(r => r.End.HasValue ? string.Format("{0}-{1}", r.Start, r.End) : r.Start.ToString());
  44.             Console.Write(string.Join(",",ranges.ToArray()));
  45. 	}
  46. }
Success #stdin #stdout 0.05s 38152KB
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1-4,8-10,15
https://ideone.com/9ckGD0
language:
C# (gmcs 5.20.1)
created:
12 years ago
visibility:
public

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