ACM-ICPC Problem Setting Best Practices

Overview

Comprehensive guidance for creating high-quality algorithm competition problems, covering the full workflow from idea conception to publication.

When to Use

• Creating problems for ACM-ICPC, CCPC, Codeforces, or similar contests
• Writing problem statements with LaTeX
• Generating test data using testlib
• Setting up validators and checkers
• Organizing algorithm competitions

Quick Reference

Topic	Detailed Rules
Problem conception	rules/problem-conception.md
Statement writing	rules/statement-writing.md
Test data generation	rules/test-data-generation.md
Special Judge	rules/spj-checker.md
Time/memory limits	rules/limits-subtasks.md
Contest organization	rules/contest-organization.md

Core Principles

Problem Quality

• Original idea - No duplicates or trivial enhancements
• Clear statement - Every concept defined, no ambiguity
• Complete constraints - All variable ranges specified
• Strong samples - Catch wrong interpretations

Data Quality

• Edge cases - Min/max values, boundary conditions
• Diverse constructions - Random + handcrafted
• Format compliance - Linux line endings, no trailing whitespace

Platform-Specific

• Polygon - Integrated workflow for teams
• Codeforces - Requires 5-25 rated contests
• Luogu - Requires competition awards

Red Flags - STOP

Anti-pattern	Fix
Undefined terms in statement	Add definitions in problem description
Inconsistent terminology	Use same word for same concept
Weak samples	Include edge cases and wrong interpretations
Incomplete data ranges	Specify ALL variables' ranges
Wrong time limit	Test std × 2 minimum
Poor subtask design	Use clear structure, avoid percentages

Essential Code

testlib Generator

#include "testlib.h"
int main(int argc, char* argv[]) {
    registerGen(argc, argv, 1);
    int n = opt<int>("n");
    vector<int> a(n);
    for (int i = 0; i < n; i++)
        a[i] = rnd.next(1, 1000000);
    println(n);
    println(a);
}

Basic Checker

#include "testlib.h"
int main(int argc, char* argv[]) {
    registerTestlibCmd(argc, argv);
    int jans = ans.readInt();
    int pans = ouf.readInt();
    if (pans == jans) quitf(_ok, "%d", pans);
    else quitf(_wa, "expected %d, found %d", jans, pans);
}

References

• OI Wiki - Problem Setting
• testlib Documentation
• Polygon Platform