private boolean allAdjacentUnColored(Collection<Vertex<Integer>> vertexes, Map<Long,String> colorsAssigned){
        for(Vertex<Integer> vertex : vertexes){
            if(colorsAssigned.containsKey(vertex.getId())){
                return false;
            }
        }
        return true;
    }
http://www.geeksforgeeks.org/graph-coloring-set-2-greedy-algorithm/
src/com/interview/graph/GraphColoring.java