Programs written in C# language are compiled on the server with .NET 8.0 (.NET SDK 8.0.100 x64, C# 12). The compiler is invoked with the following arguments:

dotnet.exe csc.dll -optimize+ -define:ONLINE_JUDGE %1

Examples of solving problems

This is a sample solution for the A + B problem in the C# language:

var tokens = Console.ReadLine().Split();
var a = int.Parse(tokens[0]);
var b = int.Parse(tokens[1]);
Console.WriteLine(a + b);

Here is an example of a simple solution for the Reverse root problem in the C# language. It demonstrates some language features but it’s not the most efficient one. With character by character input you can get much less working time and memory usage.

System.Globalization.CultureInfo.DefaultThreadCurrentCulture =
   System.Globalization.CultureInfo.InvariantCulture;

var result = Console.In.ReadToEnd()
   .Split()
   .Where(s => s != "")
   .Select(double.Parse)
   .Reverse()
   .Select(Math.Sqrt);

foreach (var d in result)
   Console.WriteLine($"{d:0.####}");

Input/output

The standard input/output methods like Console.ReadLine, String.Split and Console.WriteLine are not always sufficient. In some problems it’s necessary to manually implement fast input reading or output formatting.

In some problems numbers are not necessarily separated with a single space. Instead of

Console.ReadLine().Split()

use this code

Console.ReadLine().Split().Where(s => s != "")

Do not forget that the program can have any default culture. This is important when you need to read or write floating-point numbers: decimal separator can be configured in the system equal to either “.” or “,”. Currently the separator is set to “.” on the server, but it may be changed in the future. In order not to face culture problems pass invariant culture to all parse/formatting operation or set default culture for whole program:

System.Globalization.CultureInfo.DefaultThreadCurrentCulture =
   System.Globalization.CultureInfo.InvariantCulture;

How to increase the size of a stack

The default size of a stack is set to 1 MB.

To increase the size of a stack and to avoid its overflow when using a “deep” recursion, you should run the solution in a separate thread using the Thread constructor with two parameters. In the example, the size of the stack is set to be 16 MB, and the code of the method Main is moved to a static method Solve.

public static void Main()
{
	var T = new Thread(Solve, 16777216);
	T.Start();
}

Version history

Name	From	To	Language	Runtime
C# .NET 2.0	December 31, 2006	February 8, 2009	C# 2.0	.NET Framework 2.0
C# .NET 3.5	February 8, 2009	August 4, 2010	C# 3.0	.NET Framework 3.5
C# .NET 4.0	August 4, 2010	September 21, 2015	C# 4.0	.NET Framework 4.0
VB .NET 4.0	February 18, 2013	September 1, 2017	VB 10.0	.NET Framework 4.0
C# .NET 4.5	September 21, 2015	September 1, 2017	C# 5.0	.NET Framework 4.5
C# .NET 4.7	September 1, 2017	September 1, 2019	C# 7.1	.NET Framework 4.7
C# .NET 4.7.2	September 1, 2019	September 1, 2020	C# 7.1	.NET Framework 4.7.2
C# .NET Core 3.1	September 1, 2020	January, 22 2024	C# 8.0	.NET Core 3.1.4
C# .NET 8	January, 22 2024		C# 12.0	.NET 8.0.0