#include<stdio.h>
#include<string.h>

#define nodes 5

int graph[nodes][nodes]={
	0,1,1,1,0,
	1,0,1,1,1,
	1,1,0,1,1,
	1,1,1,0,0,
	1,1,1,0,0
};

typedef struct color_arcs{
	
	int n;
	int coloured;
	int color_index[4];
	char color[10];
}color_arcs;

color_arcs ca[nodes];

char *colors[4]={"red","blue","green","yellow"};

int arcs[nodes];
int pos=0;

void color_the_arc(int k)
{
	int i;
	printf("\nexamining node:%2d",k);
	for(i=0;i<4;i++)
	{
		ca[k].color_index[i]=1;
	}
	
	for(i=0;i<k;i++)
	{
		if(graph[k][i]==1){
		ca[k].color_index[ca[i].n]=0;
		}
	}
	for(i=0;i<4;i++)
	{
		if(ca[k].color_index[i]==1)
		{
			strcpy(ca[k].color,colors[i]);
			ca[k].n=i;
			ca[k].coloured=1;
			break;
		}
	}
	printf("\narc %d = %s color!!!\n",k,ca[k].color);
}


void find_neighbors(int k)
{
	int i;
	for(i=0;i<nodes;i++)
	{
		if(i!=k)
		{
			if(graph[k][i]==1)
			{
				arcs[pos++]=i;
			}
		}
	}
}

void set_the_color()
{
	int i,j;
	for(i=0;i<nodes;i++)
	{
		ca[i].coloured=0;
		for(j=0;j<4;j++)
		{
			ca[i].color_index[j]=1;
		}
	}
}

int main()
{
	int i,j,k;
	set_the_color();
	strcpy(ca[0].color,"red");
	ca[0].n=0;
	ca[0].color_index[0]=1;
	ca[0].color_index[1]=0;
	ca[0].color_index[2]=0;
	ca[0].color_index[3]=0;
	printf("arc 0 = %s color!!!\n",ca[0].color);
	for(i=0;i<nodes;i++)
	{
		pos=0;
		find_neighbors(i);//0:1
		for(j=0;j<pos;j++)//pos=3
		{
			if(ca[arcs[j]].coloured==0){
			color_the_arc(arcs[j]);
		}
		}
	}
	
	for(i=0;i<nodes;i++)
	{
		if(i!=4 && graph[4][i]==1)
		{
			ca[4].color_index[ca[i].n]=0;
		}
	}
	for(i=0;i<4;i++)
	{
		if(ca[4].color_index[i]==1)
		{
			ca[4].n=i;
			strcpy(ca[4].color,colors[i]);
			printf("\n%s",ca[4].color);
			ca[4].coloured=1;
			break;
		}
	}
	printf("\narc 4 = %s color!!!",ca[4].color);
	return 0;
}