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dijkstra algorithm c#

PrashantUnity answered on December 10, 2022 Popularity 7/10 Helpfulness 6/10

answer dijkstra algorithm c#

dijkstra algorithm c#

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using System;
using System.Collections.Generic;
using System.Linq;

public class Graph
{
    private Dictionary<int, Dictionary<int, int>> adjacencyList;

    public Graph()
    {
        adjacencyList = new Dictionary<int, Dictionary<int, int>>();
    }

    public void AddVertex(int vertex)
    {
        if (!adjacencyList.ContainsKey(vertex))
        {
            adjacencyList[vertex] = new Dictionary<int, int>();
        }
    }

    public void AddEdge(int source, int destination, int weight)
    {
        AddVertex(source);
        AddVertex(destination);
        adjacencyList[source][destination] = weight;
        adjacencyList[destination][source] = weight;
    }

    public Dictionary<int, int> GetShortestPaths(int start)
    {
        var distances = new Dictionary<int, int>();
        var visited = new HashSet<int>();
        var queue = new PriorityQueue<int, int>();

        foreach (var vertex in adjacencyList.Keys)
        {
            distances[vertex] = int.MaxValue;
        }

        distances[start] = 0;
        queue.Enqueue(start, 0);

        while (queue.Count > 0)
        {
            var current = queue.Dequeue();
            visited.Add(current);

            foreach (var neighbor in adjacencyList[current].Keys)
            {
                if (visited.Contains(neighbor))
                {
                    continue;
                }

                var newDistance = distances[current] + adjacencyList[current][neighbor];

                if (newDistance < distances[neighbor])
                {
                    distances[neighbor] = newDistance;
                    queue.Enqueue(neighbor, newDistance);
                }
            }
        }

        return distances;
    }
}

public class PriorityQueue<T, TPriority>
{
    private readonly List<KeyValuePair<T, TPriority>> elements = new List<KeyValuePair<T, TPriority>>();

    public int Count => elements.Count;

    public void Enqueue(T item, TPriority priority)
    {
        elements.Add(new KeyValuePair<T, TPriority>(item, priority));
    }

    public T Dequeue()
    {
        var minIndex = 0;

        for (var i = 1; i < elements.Count; i++)
        {
            if (elements[i].Value.CompareTo(elements[minIndex].Value) < 0)
            {
                minIndex = i;
            }
        }

        var min = elements[minIndex];
        elements.RemoveAt(minIndex);

        return min.Key;
    }
}

Popularity 7/10 Helpfulness 6/10 Language csharp

Source: Grepper

Tags: algorithm c# dijkstra

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Contributed on Dec 10 2022

PrashantUnity

0 Answers Avg Quality 2/10

dijkstra algorithm c#

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