Find character with most occurrences in string?

Question

For example, I have a string:

"abbbbccd" 

b has the most occurrences. When using C++, the easiest way to handle this is inserting each character into a map<>. Do I have to do the same thing in C#? Is there an elegant way to do it using LINQ?

Answer 1

input.GroupBy(x => x).OrderByDescending(x => x.Count()).First().Key 

Notes:

• if you need this to work on ancient (2.0) versions of .Net consider LinqBridge. If you can't use C# 3.0 (targeting .Net 2.0) you probably better off with other solutions due to missing lambda support. Another .Net 2.0+ option is covered in xanatos answer.
• for the case of "aaaabbbb" only one of those will be returned (thanks xanatos for comment). If you need all of the elements with maximum count, use Albin's solution instead.
• due to sorting this if O(n log n) solution. If you need better than that - find Max value by linear search instead of sorting first which will give O(n). See LINQ: How to perform .Max() on a property of all objects in a collection and return the object with maximum value