static void Main()
{
// The input is entered in same format as the prev task ( Pesho's friends )
// example:
//8 9
//1 2 20
//1 7 2
//7 8 6
//7 6 3
//6 2 1
//6 5 1
//5 3 4
//3 4 8
//3 2 5
#region Read Input
var firstLine = Console.ReadLine();
var firstLineParts = firstLine.Split(' ');
var numNodes = int.Parse(firstLineParts[0]);
var numStreets = int.Parse(firstLineParts[1]);
Dictionary<Node, List<Connection>> graph = new Dictionary<Node, List<Connection>>();
List<Node> nodes = new List<Node>();
for (int i = 1; i <= numNodes; i++)
{
var node = new Node(i);
node.DijkstraDistance = int.MaxValue;
nodes.Add(node);
graph.Add(nodes[i - 1], new List<Connection>());
}
for (int i = 0; i < numStreets; i++)
{
var currConnection = Console.ReadLine().Split(' ');
var currNode = int.Parse(currConnection[0]);
var to = int.Parse(currConnection[1]);
var distance = int.Parse(currConnection[2]);
graph[nodes[currNode - 1]].Add(new Connection(nodes[to - 1], distance));
graph[nodes[to - 1]].Add(new Connection(nodes[currNode - 1], distance));
}
#endregion;
#region Get Optimal Path
var optimalPath = double.PositiveInfinity;
var source = -1;
for (int i = 1; i < numNodes; i++)
{
var currPath = 0d;
DijkstraAlgorithm(graph, nodes[i - 1]);
for (int j = 0; j < nodes.Count; j++)
{
currPath += nodes[j].DijkstraDistance;
}
if (currPath < optimalPath)
{
source = i;
optimalPath = currPath;
}
}
#endregion;
// optional
#region Print optimal path
//Console.WriteLine(optimalPath);
//Console.WriteLine(source);
//DijkstraAlgorithm(graph, nodes[source - 1]);
//for (int i = 0; i < nodes.Count; i++)
//{
// Console.Write("Distance from {0} to {1} ", source, i + 1);
// Console.WriteLine(nodes[i].DijkstraDistance);
//}
#endregion
}
static void DijkstraAlgorithm(Dictionary<Node, List<Connection>> graph, Node source)
{
PriorityQueue<Node> queue = new PriorityQueue<Node>();
foreach (var node in graph)
{
if (source.ID != node.Key.ID)
{
node.Key.DijkstraDistance = double.PositiveInfinity;
queue.Enqueue(node.Key);
}
}
source.DijkstraDistance = 0.0d;
queue.Enqueue(source);
while (queue.Count != 0)
{
Node currentNode = queue.Peek();
if (currentNode.DijkstraDistance == double.PositiveInfinity)
{
break;
}
foreach (var neighbour in graph[currentNode])
{
double potDistance = currentNode.DijkstraDistance + neighbour.Distance;
if (potDistance < neighbour.To.DijkstraDistance)
{
neighbour.To.DijkstraDistance = potDistance;
}
}
queue.Dequeue();
}
}
public Connection(Node To, int distance)
{
this.To = To;
this.Distance = distance;
}