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Arena

Arena is the contest interface where participants solve problems during competitions. It provides a real-time problem-solving environment with live scoreboard updates, code submission, and instant feedback.

Overview

The Arena is the heart of the omegaUp contest experience, providing:

  • Problem Display: View problem statements with math rendering
  • Code Editor: Monaco-based editor with syntax highlighting
  • Submission System: Submit solutions and view detailed results
  • Live Scoreboard: Real-time contest rankings
  • Clarifications: Q&A system for contest questions
  • Timer: Contest countdown and time tracking

Arena Layout

┌─────────────────────────────────────────────────────────────┐
│  Contest Title                              Timer: 01:30:00 │
├─────────┬───────────────────────────────────────────────────┤
│         │                                                   │
│ Problem │              Problem Statement                    │
│  List   │                                                   │
│         │  - Description                                    │
│  [A]    │  - Input/Output format                           │
│  [B]    │  - Constraints                                   │
│  [C]    │  - Examples                                      │
│         │                                                   │
│─────────┼───────────────────────────────────────────────────│
│         │                                                   │
│ Submit  │              Code Editor                          │
│ History │                                                   │
│         │  [Language: C++17 ▼]  [Submit]                   │
│         │                                                   │
├─────────┴───────────────────────────────────────────────────┤
│                    Scoreboard / Clarifications              │
└─────────────────────────────────────────────────────────────┘

User Flow

flowchart TD
    A[Enter Contest] --> B[View Problem List]
    B --> C[Select Problem]
    C --> D[Read Statement]
    D --> E[Write Solution]
    E --> F[Choose Language]
    F --> G[Submit Code]
    G --> H{Verdict}
    H -->|AC| I[Problem Solved]
    H -->|WA/TLE/etc| J[Debug]
    J --> E
    I --> K[Check Scoreboard]
    K --> L{More Problems?}
    L -->|Yes| C
    L -->|No| M[Wait for Contest End]

Key Components

Problem Panel

The problem panel displays:

Element Description
Statement Problem description with LaTeX math support
Input Format Expected input specification
Output Format Required output format
Constraints Time limit, memory limit, input bounds
Examples Sample input/output pairs
Notes Additional hints or clarifications

Math Rendering: 

$$ \sum_{i=1}^{n} a_i \leq 10^9 $$

Code Editor

Monaco Editor features:

  • Syntax Highlighting: Language-specific coloring
  • Auto-completion: Basic code completion
  • Line Numbers: Easy reference
  • Keyboard Shortcuts: Standard editor shortcuts
  • Theme: Light/dark mode support

Supported Languages:

Language Extension Version
C++ 17 .cpp GCC 10+
C++ 11 .cpp GCC 10+
Java .java OpenJDK 17
Python 3 .py 3.10+
Python 2 .py 2.7
C .c GCC 10+
Karel .kp, .kj Custom
Pascal .pas FPC 3.2

Submission System

Submit Flow

  1. Select language from dropdown
  2. Paste or type code in editor
  3. Click "Submit" button
  4. Wait for verdict (real-time updates)

Verdict Display

Verdict Color Meaning
AC Green Accepted - all tests passed
PA Yellow Partial - some tests passed
WA Red Wrong Answer
TLE Orange Time Limit Exceeded
MLE Orange Memory Limit Exceeded
RTE Red Runtime Error
CE Gray Compilation Error

Submission Details

Clicking a submission shows:

  • Verdict per test case (if allowed)
  • Runtime and memory usage
  • Compilation output (if CE)
  • Score breakdown (partial scoring)

Scoreboard

Real-time scoreboard showing:

Column Description
Rank Current position
User Participant name
Score Total points
Penalty Time penalty (ICPC)
Per-problem Status per problem

Problem Status Icons:

  • ✓ (green): Accepted
  • ✗ (red): Wrong Answer attempts
  • ? (yellow): Pending judgment
    • (gray): Not attempted

Clarifications

Q&A system for contests:

  1. Ask: Submit question about a problem
  2. View: See public clarifications
  3. Notifications: Real-time alerts for answers

Clarification Types:

  • Public: Visible to all participants
  • Private: Only for the asking participant

Contest Modes

Practice Mode

Outside contest times:

  • No time pressure
  • Full verdict details visible
  • No scoreboard impact
  • Unlimited submissions

Contest Mode

During contest:

  • Timer counting down
  • Limited verdict info (configurable)
  • Live scoreboard
  • Submission limits may apply

Virtual Contest

Simulate past contests:

  • Original time limits
  • Original problems
  • Personal timer
  • Compare with original results

Real-time Features

WebSocket Updates

Arena uses WebSocket for real-time updates:

// Events received
- 'run_update': Submission verdict changed
- 'scoreboard_update': Scoreboard refreshed
- 'clarification': New clarification posted

Notifications

Desktop notifications for:

  • Submission judged
  • New clarification
  • Contest ending soon (15 min, 5 min)

Keyboard Shortcuts

Shortcut Action
Ctrl+Enter Submit code
Ctrl+S Save draft (local)
Esc Close modal
1-9 Switch to problem 1-9

Contest Admin View

Contest admins see additional features:

  • All Submissions: View all participant submissions
  • Rejudge: Rejudge specific submissions
  • Broadcast: Send announcements
  • Answer Clarifications: Respond to questions
  • Extend Time: Add contest time

Mobile Support

Arena is responsive and supports:

  • Tablet viewing (problem reading)
  • Mobile submission (limited)
  • Scoreboard viewing

Performance

Arena optimizations:

  • Lazy Loading: Problems loaded on demand
  • Caching: Scoreboard cached and diff-updated
  • Compression: Gzipped responses
  • CDN: Static assets on CDN