feat: add cs solution to lc problem: No.1743 (doocs#1952)

Author: dev-mauli

solution/1700-1799/1743.Restore the Array From Adjacent Pairs/README.md

@@ -292,6 +292,46 @@ func restoreArray(adjacentPairs [][]int) []int {
 }
 ```
 
+### **C#**
+
+```cs
+public class Solution {
+    public int[] RestoreArray(int[][] adjacentPairs) {
+        int n = adjacentPairs.Length + 1;
+        Dictionary<int, List<int>> g = new Dictionary<int, List<int>>();
+
+        foreach (int[] e in adjacentPairs) {
+            int a = e[0], b = e[1];
+            if (!g.ContainsKey(a)) {
+                g[a] = new List<int>();
+            }
+            if (!g.ContainsKey(b)) {
+                g[b] = new List<int>();
+            }
+            g[a].Add(b);
+            g[b].Add(a);
+        }
+
+        int[] ans = new int[n];
+
+        foreach (var entry in g) {
+            if (entry.Value.Count == 1) {
+                ans[0] = entry.Key;
+                ans[1] = entry.Value[0];
+                break;
+            }
+        }
+
+        for (int i = 2; i < n; ++i) {
+            List<int> v = g[ans[i - 1]];
+            ans[i] = v[1] == ans[i - 2] ? v[0] : v[1];
+        }
+
+        return ans;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1700-1799/1743.Restore the Array From Adjacent Pairs/README_EN.md

@@ -278,6 +278,46 @@ func restoreArray(adjacentPairs [][]int) []int {
 }
 ```
 
+### **C#**
+
+```cs
+public class Solution {
+    public int[] RestoreArray(int[][] adjacentPairs) {
+        int n = adjacentPairs.Length + 1;
+        Dictionary<int, List<int>> g = new Dictionary<int, List<int>>();
+
+        foreach (int[] e in adjacentPairs) {
+            int a = e[0], b = e[1];
+            if (!g.ContainsKey(a)) {
+                g[a] = new List<int>();
+            }
+            if (!g.ContainsKey(b)) {
+                g[b] = new List<int>();
+            }
+            g[a].Add(b);
+            g[b].Add(a);
+        }
+
+        int[] ans = new int[n];
+
+        foreach (var entry in g) {
+            if (entry.Value.Count == 1) {
+                ans[0] = entry.Key;
+                ans[1] = entry.Value[0];
+                break;
+            }
+        }
+
+        for (int i = 2; i < n; ++i) {
+            List<int> v = g[ans[i - 1]];
+            ans[i] = v[1] == ans[i - 2] ? v[0] : v[1];
+        }
+
+        return ans;
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1700-1799/1743.Restore the Array From Adjacent Pairs/Solution.cs

@@ -0,0 +1,35 @@
+public class Solution {
+    public int[] RestoreArray(int[][] adjacentPairs) {
+        int n = adjacentPairs.Length + 1;
+        Dictionary<int, List<int>> g = new Dictionary<int, List<int>>();
+        
+        foreach (int[] e in adjacentPairs) {
+            int a = e[0], b = e[1];
+            if (!g.ContainsKey(a)) {
+                g[a] = new List<int>();
+            }
+            if (!g.ContainsKey(b)) {
+                g[b] = new List<int>();
+            }
+            g[a].Add(b);
+            g[b].Add(a);
+        }
+        
+        int[] ans = new int[n];
+        
+        foreach (var entry in g) {
+            if (entry.Value.Count == 1) {
+                ans[0] = entry.Key;
+                ans[1] = entry.Value[0];
+                break;
+            }
+        }
+        
+        for (int i = 2; i < n; ++i) {
+            List<int> v = g[ans[i - 1]];
+            ans[i] = v[1] == ans[i - 2] ? v[0] : v[1];
+        }
+        
+        return ans;
+    }
+}