How to generator all combinations (memory efficient algorithm)?

by

Just create an iterator method using yield return, like so: 

   public class Combinations: IEnumerable<Combination> {
        public IEnumerator<T> GetEnumerator()
        {
            Combination currentCombination = Combination.FirstCombination(); 
            while (currentCombination.IsValid()) {
                yield return currentCombination;
                currentCombination = currentCombination.NextCombination(); // return invalid combo if currentCombination is the last possible combination
            }
        }
   }

Of course you still have to write the Combination class but that should be relatively straightforward. You should be able to generate the next combination from the current one. For example, say there are N elements in the list, you just have to increment a base-N number containing N digits and as you do that you will generate all combinations.

More Related Contents:

  1. Ordered Unique Combinations [closed]
  2. Memory leak in Data Access layer using enterprise library
  3. Different combinations of an array (C#)
  4. Setting Objects to Null/Nothing after use in .NET
  5. All Possible Combinations of a list of Values
  6. Does using “new” on a struct allocate it on the heap or stack?
  7. How to get memory available or used in C#
  8. Implementing IDisposable correctly
  9. What strategies and tools are useful for finding memory leaks in .NET?
  10. Large Object Heap Fragmentation
  11. Is there any benefit of using an Object Initializer?
  12. ‘System.OutOfMemoryException’ was thrown when there is still plenty of memory free
  13. .NET Memory issues loading ~40 images, memory not reclaimed, potentially due to LOH fragmentation
  14. Combination Generator in Linq
  15. Are these objects’s references on the Stack or on the Heap?
  16. Fields of class, are they stored in the stack or heap?
  17. C# memory address and variable
  18. Why is 16 byte the recommended size for struct in C#?
  19. Why am I getting an Out Of Memory Exception in my C# application?
  20. How to calculate private working set (memory)?
  21. How is memory allocated for a static variable?
  22. Most efficient way to append arrays in C#?
  23. What causes memory fragmentation in .NET
  24. Generate all combinations for a list of strings
  25. How are String and Char types stored in memory in .NET?
  26. How do I get .NET to garbage collect aggressively?
  27. Memory limitations in a 64-bit .Net application?
  28. Get all pairs in a list using LINQ
  29. Large Object Heap Compaction, when is it good?
  30. How can I create all possible combinations for a set of words without repetition?

Leave a Comment