Tags API

The Tags API provides endpoints for searching and retrieving problem tags used for categorization and filtering.

Overview

Tags in omegaUp categorize problems by:

Topic: Algorithm or data structure (e.g., Dynamic Programming, Graphs)
Level: Difficulty tier (e.g., Basic, Intermediate, Advanced)
Source: Origin or competition (e.g., IOI, ICPC, OMI)

Endpoints

Searches for tags matching a query.

GET /api/tag/list/

Parameters:

Parameter	Type	Required	Description
`query`	string	Yes*	Search term
`term`	string	Yes*	Alternative search parameter

*One of query or term is required.

Response:

[
  { "name": "problemTopicDynamicProgramming" },
  { "name": "problemTopicGraphTheory" },
  { "name": "problemTopicGreedy" }
]

Privileges: Public (no authentication required)

Get Frequent Tags

Returns the most frequently used tags for a given problem level.

GET /api/tag/frequentTags/

Parameters:

Parameter	Type	Required	Description
`problemLevel`	string	Yes	Level tag (e.g., `problemLevelBasicKarel`)
`rows`	int	Yes	Number of tags to return

Response:

{
  "frequent_tags": [
    { "name": "problemTopicLoops", "problemCount": 150 },
    { "name": "problemTopicArrays", "problemCount": 120 },
    { "name": "problemTopicConditionals", "problemCount": 95 }
  ]
}

Privileges: Public

Tag Categories

Topic Tags (`problemTopic*`)

Algorithm and data structure categories:

Tag	Description
`problemTopicArrays`	Array manipulation
`problemTopicBinarySearch`	Binary search algorithms
`problemTopicDynamicProgramming`	DP techniques
`problemTopicGraphTheory`	Graph algorithms
`problemTopicGreedy`	Greedy algorithms
`problemTopicMath`	Mathematical problems
`problemTopicStrings`	String processing
`problemTopicTrees`	Tree structures
`problemTopicSorting`	Sorting algorithms
`problemTopicDataStructures`	Advanced data structures
`problemTopicGeometry`	Computational geometry
`problemTopicNumberTheory`	Number theory
`problemTopicCombinatorics`	Combinatorics
`problemTopicBitmasks`	Bitmask operations
`problemTopicSimulation`	Simulation problems

Level Tags (`problemLevel*`)

Difficulty classification:

Tag	Description
`problemLevelBasicKarel`	Karel beginner level
`problemLevelBasicIntroductionToProgramming`	Programming basics
`problemLevelIntermediateDataStructuresAndAlgorithms`	Intermediate DS/Algo
`problemLevelIntermediateMathsInProgramming`	Math in programming
`problemLevelIntermediateAnalysisAndDesignOfAlgorithms`	Algorithm design
`problemLevelAdvancedCompetitiveProgramming`	Competitive programming
`problemLevelAdvancedSpecializedTopics`	Specialized advanced

Public Tags (`problemTag*`)

Fine-grained categorization for public problems:

Tag	Description
`problemTagArithmetic`	Basic arithmetic
`problemTagConditionals`	If/else statements
`problemTagLoops`	Loop constructs
`problemTagFunctions`	Functions and procedures
`problemTagRecursion`	Recursive solutions
`problemTagDynamicProgramming`	DP problems
`problemTagBreadthFirstSearch`	BFS traversal
`problemTagDepthFirstSearch`	DFS traversal
`problemTagShortestPaths`	Shortest path algorithms
...	(many more available)

Competition Tags

Source/origin tags:

Tag	Description
`problemTagIOI`	International Olympiad in Informatics
`problemTagICPC`	International Collegiate Programming Contest
`problemTagOMI`	Mexican Olympiad in Informatics
`problemTagCOCI`	Croatian Open Competition
`problemTagBOI`	Baltic Olympiad

Tag Normalization

Tags are normalized before storage:

Convert to lowercase
Remove accents
Replace non-alphanumeric with hyphens
Collapse multiple hyphens

// Example: "Árbol Binário!" → "arbol-binario"

Use Cases

Search for Tags (Autocomplete)

// Search tags as user types
const response = await fetch('/api/tag/list/?query=graph');
const tags = await response.json();
// Returns: [{ name: "problemTopicGraphTheory" }, ...]

Get Popular Tags for a Level

// Get top 10 tags for basic programming
const response = await fetch(
  '/api/tag/frequentTags/?problemLevel=problemLevelBasicIntroductionToProgramming&rows=10'
);
const { frequent_tags } = await response.json();

Filter Problems by Tag

Tags are used with the Problems API to filter:

# Get problems with a specific tag
curl "https://omegaup.com/api/problem/list/?tag=problemTopicDynamicProgramming"

Tag Sources

Tags come from:

Problem authors: Added during problem creation
Quality nominations: Community suggestions
Quality reviewers: Official tag assignments
System: Automatic categorization

Problems API - Problem listing with tag filters
Quality Nominations API - Tag suggestions

Full Reference

For complete tag lists and implementation, see the Tag Controller and QualityNomination Controller for allowed tags.