Solution.cs

public class Graph {
    private int n;
    private int[][] g;
    private readonly int inf = 1 << 29;

    public Graph(int n, int[][] edges) {
        this.n = n;
        g = new int[n][];
        for (int i = 0; i < n; i++)
        {
            g[i] = new int[n];
            for (int j = 0; j < n; j++)
            {
                g[i][j] = inf;
            }
        }
        foreach (int[] e in edges)
        {
            g[e[0]][e[1]] = e[2];
        }
    }
    
    public void AddEdge(int[] edge) {
        g[edge[0]][edge[1]] = edge[2];
    }
    
    public int ShortestPath(int node1, int node2) {
        int[] dist = new int[n];
        bool[] vis = new bool[n];
        Array.Fill(dist, inf);
        dist[node1] = 0;

        for (int i = 0; i < n; i++)
        {
            int t = -1;
            for (int j = 0; j < n; j++)
            {
                if (!vis[j] && (t == -1 || dist[t] > dist[j]))
                    t = j;
            }
            vis[t] = true;
            for (int j = 0; j < n; j++)
            {
                dist[j] = Math.Min(dist[j], dist[t] + g[t][j]);
            }
        }
        return dist[node2] >= inf ? -1 : dist[node2];
    }
}

/**
 * Your Graph object will be instantiated and called as such:
 * Graph obj = new Graph(n, edges);
 * obj.AddEdge(edge);
 * int param_2 = obj.ShortestPath(node1,node2);
 */