feat: add cs solution to lc problem: No.2642 (doocs#1953)

* feat: add solution.cs to lc problems: No.2642

* Update README_EN.md to lc problems: No.2642

* Update README.md to lc problems: No.2642

* style: format code and docs with prettier

---------

Co-authored-by: dev-mauli <dev-mauli@users.noreply.github.com>

Author: dev-mauli

solution/2600-2699/2642.Design Graph With Shortest Path Calculator/README.md

@@ -323,6 +323,67 @@ class Graph {
  */
 ```
 
+### **C#**
+
+```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);
+ */
+```
+
 ### **...**
 
 ```

solution/2600-2699/2642.Design Graph With Shortest Path Calculator/README_EN.md

@@ -303,6 +303,67 @@ class Graph {
  */
 ```
 
+### **C#**
+
+```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);
+ */
+```
+
 ### **...**
 
 ```

solution/2600-2699/2642.Design Graph With Shortest Path Calculator/Solution.cs

@@ -0,0 +1,56 @@
+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);
+ */