#include "graph1.h"
#include "cstdlib"

graph::graph(){
	// Nothing needs to be done except set the number of nodes to zero
	myNumberNodes = 0;
}

void graph::operator +=(const node & x){
	
	// If the vector of nodes is full, resize it and resize the adjacency 
	// matrix. We'll make sure thet the length of the node vector always
	// equals the dimensions of the adjacency matrix
	if(myNumberNodes == myNodes.length()){
		myNodes.resize(2*myNumberNodes+1);
		myMatrix.resize(2*myNumberNodes+1);
		for(int i = 0; i <= 2*myNumberNodes; i++)
			myMatrix[i].resize(2*myNumberNodes+1);
	}

	// Insert the new node at the end
	myNodes[myNumberNodes] = x;

	// Since the new node has no neighbors to start with, set the
	// corresponding row and column to false
	for(int i = 0; i <= myNumberNodes; i++){
		myMatrix[myNumberNodes][i] = false;
		myMatrix[i][myNumberNodes] = false;
	}

	myNumberNodes++;

}

void graph::operator +=(const edge & x){
	// Get the indices of the two endpoints of the edge in the vector of
	// nodes
	int i = getIndex(x.getNode1());
	int j = getIndex(x.getNode2());

	// Use these indices to turn on the corresponding elements in the 
	// adjacency matrix
	myMatrix[i][j] = myMatrix[j][i] = true;
}

apvector<node> graph::get_neighbors(const node & x){
	// Get the index of the node	
	int i = getIndex(x);

	// Set up a vector for the list of neighbors
	apvector<node> neighbors;	

	// Scan the row corresponding to the node x in the adjacency matrix
	// and pick up neighboring nodes
	for(int j = 0; j < myNumberNodes; j++)
	       if(myMatrix[i][j])
			neighbors.push_back(myNodes[j]);
	return neighbors;
}

int graph::getIndex(const node & x){
	for(int i = 0; i < myNumberNodes; i++)
		if(x == myNodes[i])
			return i;	
	return -1;
}