Solution: Graph Coloring

#include "Graph.h"
void Graph::greedyColoring() {
  int * result = new int[this -> vertices];
  // Assign the first color to first vertex 
  result[0] = 0;
  // Initialize remaining V-1 vertices as unassigned 
  for (int u = 1; u < this -> vertices; u++)
    result[u] = -1; // no color is assigned to u 
  bool available[this -> vertices];
  for (int color = 0; color < this -> vertices; color++)
    available[color] = false;
  // Assign colors to remaining V-1 vertices 
  for (int u = 1; u < this -> vertices; u++) {
    list < int > ::iterator i;
    for (i = adjacencyList[u].begin(); i != adjacencyList[u].end(); ++i)
      if (result[ * i] != -1)
        available[result[ * i]] = true;
    // Find the first available color 
    int color;
    for (color = 0; color < this -> vertices; color++)
      if (available[color] == false)
        break;
    result[u] = color; // Assign the found color 
    // Reset the values  
    for (i = adjacencyList[u].begin(); i != adjacencyList[u].end(); ++i)
      if (result[ * i] != -1)
        available[result[ * i]] = false;
  }
  for (int u = 0; u < this -> vertices; u++)
    cout << "Vertex " << u << " ---> Color " <<
    result[u] << endl;
  
  delete result;
}
int main() {
  Graph g1(5);
  g1.addEdge(0, 1);
  g1.addEdge(0, 2);
  g1.addEdge(1, 2);
  g1.addEdge(1, 3);
  g1.addEdge(2, 3);
  g1.addEdge(3, 4);
  cout << "Coloring of graph 1 \n";
  g1.greedyColoring();
  Graph g2(5);
  g2.addEdge(0, 1);
  g2.addEdge(0, 2);
  g2.addEdge(1, 2);
  g2.addEdge(1, 4);
  g2.addEdge(2, 4);
  g2.addEdge(4, 3);
  cout << "\nColoring of graph 2 \n";
  g2.greedyColoring();
  return 0;
}