`greedy_vertex_coloring()`

finds a coloring for the vertices of a graph
based on a simple greedy algorithm.

## Usage

`greedy_vertex_coloring(graph, heuristic = c("colored_neighbors", "dsatur"))`

## Arguments

- graph
The graph object to color.

- heuristic
The selection heuristic for the next vertex to consider. Possible values are: “colored_neighbors” selects the vertex with the largest number of already colored neighbors. “dsatur” selects the vertex with the largest number of unique colors in its neighborhood, i.e. its "saturation degree"; when there are several maximum saturation degree vertices, the one with the most uncolored neighbors will be selected.

## Details

The goal of vertex coloring is to assign a "color" (represented as a positive integer) to each vertex of the graph such that neighboring vertices never have the same color. This function solves the problem by considering the vertices one by one according to a heuristic, always choosing the smallest color that differs from that of already colored neighbors. The coloring obtained this way is not necessarily minimum but it can be calculated in linear time.

## Examples

```
g <- make_graph("petersen")
col <- greedy_vertex_coloring(g)
plot(g, vertex.color = col)
```