## Checker

See: vc_validate

## Input Format

### Graph (.gr)

The graph format is similar to the PACE2016 and PACE2017 graph format.

- Line separator ‘\n’
- Lines starting with character c are interpreted as comments
- Vertices are consecutively numbered from 1 to n
- Problem description
- Form “p td NumVertices NumHyperedges”
- Line starting with character p
- followed by the problem descriptor td
- followed by number n of vertices
- followed by number m of edges
- each separated by space each time

- Unique (No other line may start with p)
- Has to be the first line (except comments)

- Form “p td NumVertices NumHyperedges”
- Remaining lines indicate edges
- consisting of two decimal integers separated by space
- Line “1 3\n” indicates an edge between vertex 1 and vertex 3

- Empty lines or lines consisting of spaces may occur and only will be ignored
- Graphs may contain isolated vertices, multiple edges, and loops

Example:

```
c This file describes a graph in td PACE2019 format with 6 vertices and 4 edges
p td 6 4
1 2
2 3
c this is a comment and will be ignored
4 5
4 6
```

### Vertex Cover Format (.vc)

- Line separator ‘\n’
- Lines starting with character c are interpreted as comments
- Vertices are consecutively numbered from 1 to n
- Solution description
- Form “s vc NumVertices NumVerticesInVertexcover”
- Line starting with character s
- followed by the problem descriptor vc
- followed by number n of vertices
- followed by the number v of vertices in the vertex cover
- each separated by space each time

- Unique (No other line may start with s)
- Has to be the first line (except comments)

- Form “s vc NumVertices NumVerticesInVertexcover”
- Vertex cover description
- Lists the vertices in the vertex cover (at most v many)
- Form “Vertex”
- Lines consist only of one vertex identifier

- Empty lines or lines consisting of spaces may occur and only will be ignored

```
c This file describes for a graph with 5 vertices
c a vertex cover consisting of 2 vertices
s vc 5 2
2
4
```