shortest path c# in csharp

main.cs
using System;
using System.Collections.Generic;

class Graph
{
    private int V;                     
    private List<Tuple<int, int>>[] adj; 

    public Graph(int V)
    {
        this.V = V;
        adj = new List<Tuple<int, int>>[V];
        for (int i = 0; i < V; i++)
            adj[i] = new List<Tuple<int, int>>();
    }

    public void AddEdge(int u, int v, int w)
    {
        adj[u].Add(Tuple.Create(v, w));
        adj[v].Add(Tuple.Create(u, w));
    }

    public int[] ShortestPath(int s)
    {
        var dist = new int[V];
        for (int i = 0; i < V; i++)
            dist[i] = int.MaxValue;
        dist[s] = 0;

        var pq = new PriorityQueue<Tuple<int, int>>(V);
        pq.Enqueue(Tuple.Create(s, 0));

        while (pq.Count > 0)
        {
            var u = pq.Dequeue();
            if (u.Item2 > dist[u.Item1])
                continue;

            foreach (var v in adj[u.Item1])
            {
                var alt = dist[u.Item1] + v.Item2;
                if (alt < dist[v.Item1])
                {
                    dist[v.Item1] = alt;
                    pq.Enqueue(Tuple.Create(v.Item1, alt));
                }
            }
        }

        return dist;
    }
}

class PriorityQueue<T> where T : IComparable<T>
{
    private List<T> data;

    public PriorityQueue()
    {
        this.data = new List<T>();
    }

    public PriorityQueue(int capacity)
    {
        this.data = new List<T>(capacity);
    }

    public void Enqueue(T item)
    {
        data.Add(item);
        int ci = data.Count - 1;

        while (ci > 0)
        {
            int pi = (ci - 1) / 2;
            if (data[ci].CompareTo(data[pi]) >= 0)
                break;
            T tmp = data[ci]; data[ci] = data[pi]; data[pi] = tmp;
            ci = pi;
        }
    }

    public T Dequeue()
    {
        int li = data.Count - 1;
        T frontItem = data[0];
        data[0] = data[li];
        data.RemoveAt(li);

        --li;
        int pi = 0;
        while (true)
        {
            int ci = pi * 2 + 1;
            if (ci > li)
                break;
            int rc = ci + 1;
            if (rc <= li && data[rc].CompareTo(data[ci]) < 0)
                ci = rc;
            if (data[pi].CompareTo(data[ci]) <= 0)
                break;
            T tmp = data[pi]; data[pi] = data[ci]; data[ci] = tmp;
            pi = ci;
        }
        return frontItem;
    }

    public T Peek()
    {
        T frontItem = data[0];
        return frontItem;
    }

    public int Count()
    {
        return data.Count;
    }
}

class Program
{
    static void Main(string[] args)
    {
        var g = new Graph(5);
        g.AddEdge(0, 1, 4);
        g.AddEdge(0, 2, 1);
        g.AddEdge(2, 1, 2);
        g.AddEdge(1, 3, 1);
        g.AddEdge(2, 3, 5);
        g.AddEdge(3, 4, 3);

        int[] dist = g.ShortestPath(0);
        for (int i = 0; i < dist.Length; i++)
            Console.WriteLine("Shortest distance from 0 to " + i + " is " + dist[i]);

        Console.ReadLine();
    }
}
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