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NextJudge

Supported Languages

NextJudge supports a wide variety of programming languages for competitive programming. Each language is configured with specific compiler/runtime settings and resource limits.

Language List

Section titled “Language List”

C++

Section titled “C++”
  • Version: 13.2.0
  • Extension: .cpp
  • Compiler: g++ with -O2 optimization
  • Default Limits: Standard time and memory limits

C

Section titled “C”
  • Version: 13.2.0
  • Extension: .c
  • Compiler: gcc with -O2 optimization
  • Default Limits: Standard time and memory limits

Python

Section titled “Python”
  • Version: 3.12
  • Extension: .py
  • Runtime: Python 3.12
  • Default Limits: Standard time and memory limits

PyPy

Section titled “PyPy”
  • Version: 3.9.18 (PyPy 7.3.15)
  • Extension: .py
  • Runtime: PyPy3 for faster execution
  • Default Limits: Standard time and memory limits
  • Note: Uses PyPy for improved performance on certain algorithms

Java

Section titled “Java”
  • Version: 21.0.3
  • Extension: .java
  • Compiler: javac
  • Runtime: Java with -XX:+UseSerialGC -Xms512m -Xmx512m
  • Default Limits: 512MB memory limit
  • Note: Automatically handles class name detection

JavaScript

Section titled “JavaScript”
  • Version: 21.6.2 (Node.js)
  • Extension: .js
  • Runtime: Node.js v21.6.2
  • Default Limits: Standard time and memory limits

TypeScript

Section titled “TypeScript”
  • Version: 5.4.5
  • Extension: .ts
  • Compiler: TypeScript compiler (tsc)
  • Runtime: Node.js v21.6.2
  • Default Limits: Standard time and memory limits
  • Note: Compiles to JavaScript before execution

Go

Section titled “Go”
  • Version: 1.24.11
  • Extension: .go
  • Compiler: Go compiler with build flags
  • Default Limits: Standard time and memory limits
  • Note: Uses persistent cache directories for faster compilation

Rust

Section titled “Rust”
  • Version: 1.78.0
  • Extension: .rs
  • Compiler: rustc
  • Default Limits: Standard time and memory limits

Ruby

Section titled “Ruby”
  • Version: 3.2.3
  • Extension: .rb
  • Runtime: Ruby 3.2.3
  • Default Limits: Standard time and memory limits

Lua

Section titled “Lua”
  • Version: 5.4.6
  • Extension: .lua
  • Runtime: Lua 5.4.6
  • Default Limits: Standard time and memory limits

Kotlin

Section titled “Kotlin”
  • Version: 1.9.24
  • Extension: .kt
  • Compiler: Kotlin compiler (kotlinc)
  • Runtime: Kotlin runtime
  • Default Limits: Standard time and memory limits
  • Note: Compiles to JVM bytecode

Haskell

Section titled “Haskell”
  • Version: 9.4.7
  • Extension: .hs
  • Compiler: GHC (Glasgow Haskell Compiler)
  • Default Limits: Standard time and memory limits

Language Configuration

Section titled “Language Configuration”

Languages are configured in the judge service’s languages.toml file. Each language entry specifies:

  • name: Display name of the language
  • version: Version string for the compiler/runtime
  • extension: File extension used to identify the language
  • script: Build script that compiles or prepares the code for execution

Execution Environment

Section titled “Execution Environment”

All code execution happens in isolated environments using nsjail, which provides:

  • Process isolation
  • Resource limits (CPU time, memory, file descriptors)
  • Network restrictions
  • File system restrictions
  • User namespace isolation

Resource Limits

Section titled “Resource Limits”

Default resource limits are applied per language:

  • Time Limit: Configurable per problem (default: 5-10 seconds)
  • Memory Limit: Configurable per problem (default: 256MB-512MB)
  • CPU Cores: 1 core (2 for Go compilation)
  • File Descriptors: Limited to prevent resource exhaustion

Adding New Languages

Section titled “Adding New Languages”

To add support for a new language:

  1. Install the compiler/runtime in the judge Docker image
  2. Add a language entry to languages.toml with the build script
  3. Register the language in the data layer database
  4. Test compilation and execution with sample code

The build script should:

  • Compile the source code (if needed)
  • Create an executable script at /executable/main
  • Handle any language-specific requirements

Language-Specific Notes

Section titled “Language-Specific Notes”

Java

Section titled “Java”

Java submissions automatically handle class name detection. If the class name doesn’t match the filename, the judge will rename the file accordingly.

Go

Section titled “Go”

Go uses persistent cache directories (/go_cache and /go_mod_cache) to speed up compilation. These are mounted as writable directories in the nsjail environment.

TypeScript

Section titled “TypeScript”

TypeScript files are compiled to JavaScript before execution. The compilation happens in the build phase, and the resulting JavaScript is executed.

Kotlin

Section titled “Kotlin”

Kotlin compiles to JVM bytecode and runs using the Kotlin runtime. The default entry point is InputKt.class.