diff --git a/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/README.md b/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/README.md
index fc17eb98f7b14..f349c76c2d688 100644
--- a/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/README.md	
+++ b/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/README.md	
@@ -175,23 +175,22 @@ class Solution {
 class Solution {
 public:
     TreeNode* lcaDeepestLeaves(TreeNode* root) {
+        auto dfs = [&](this auto&& dfs, TreeNode* root) -> pair<TreeNode*, int> {
+            if (!root) {
+                return {nullptr, 0};
+            }
+            auto [l, d1] = dfs(root->left);
+            auto [r, d2] = dfs(root->right);
+            if (d1 > d2) {
+                return {l, d1 + 1};
+            }
+            if (d1 < d2) {
+                return {r, d2 + 1};
+            }
+            return {root, d1 + 1};
+        };
         return dfs(root).first;
     }
-
-    pair<TreeNode*, int> dfs(TreeNode* root) {
-        if (!root) {
-            return {nullptr, 0};
-        }
-        auto [l, d1] = dfs(root->left);
-        auto [r, d2] = dfs(root->right);
-        if (d1 > d2) {
-            return {l, d1 + 1};
-        }
-        if (d1 < d2) {
-            return {r, d2 + 1};
-        }
-        return {root, d1 + 1};
-    }
 };
 ```
 
@@ -267,6 +266,48 @@ function lcaDeepestLeaves(root: TreeNode | null): TreeNode | null {
 }
 ```
 
+#### C#
+
+```cs
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     public int val;
+ *     public TreeNode left;
+ *     public TreeNode right;
+ *     public TreeNode(int val = 0, TreeNode left = null, TreeNode right = null) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+public class Solution {
+    public TreeNode LcaDeepestLeaves(TreeNode root) {
+        (TreeNode, int) Dfs(TreeNode root) {
+            if (root == null) {
+                return (null, 0);
+            }
+
+            var l = Dfs(root.left);
+            var r = Dfs(root.right);
+            int d1 = l.Item2;
+            int d2 = r.Item2;
+
+            if (d1 > d2) {
+                return (l.Item1, d1 + 1);
+            }
+            if (d1 < d2) {
+                return (r.Item1, d2 + 1);
+            }
+            return (root, d1 + 1);
+        }
+
+        return Dfs(root).Item1;
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->
diff --git a/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/README_EN.md b/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/README_EN.md
index 91f045fc4c941..55ff2ddf2357e 100644
--- a/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/README_EN.md	
+++ b/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/README_EN.md	
@@ -172,23 +172,22 @@ class Solution {
 class Solution {
 public:
     TreeNode* lcaDeepestLeaves(TreeNode* root) {
+        auto dfs = [&](this auto&& dfs, TreeNode* root) -> pair<TreeNode*, int> {
+            if (!root) {
+                return {nullptr, 0};
+            }
+            auto [l, d1] = dfs(root->left);
+            auto [r, d2] = dfs(root->right);
+            if (d1 > d2) {
+                return {l, d1 + 1};
+            }
+            if (d1 < d2) {
+                return {r, d2 + 1};
+            }
+            return {root, d1 + 1};
+        };
         return dfs(root).first;
     }
-
-    pair<TreeNode*, int> dfs(TreeNode* root) {
-        if (!root) {
-            return {nullptr, 0};
-        }
-        auto [l, d1] = dfs(root->left);
-        auto [r, d2] = dfs(root->right);
-        if (d1 > d2) {
-            return {l, d1 + 1};
-        }
-        if (d1 < d2) {
-            return {r, d2 + 1};
-        }
-        return {root, d1 + 1};
-    }
 };
 ```
 
@@ -264,6 +263,48 @@ function lcaDeepestLeaves(root: TreeNode | null): TreeNode | null {
 }
 ```
 
+#### C#
+
+```cs
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     public int val;
+ *     public TreeNode left;
+ *     public TreeNode right;
+ *     public TreeNode(int val = 0, TreeNode left = null, TreeNode right = null) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+public class Solution {
+    public TreeNode LcaDeepestLeaves(TreeNode root) {
+        (TreeNode, int) Dfs(TreeNode root) {
+            if (root == null) {
+                return (null, 0);
+            }
+
+            var l = Dfs(root.left);
+            var r = Dfs(root.right);
+            int d1 = l.Item2;
+            int d2 = r.Item2;
+
+            if (d1 > d2) {
+                return (l.Item1, d1 + 1);
+            }
+            if (d1 < d2) {
+                return (r.Item1, d2 + 1);
+            }
+            return (root, d1 + 1);
+        }
+
+        return Dfs(root).Item1;
+    }
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->
diff --git a/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/Solution.cpp b/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/Solution.cpp
index 9bd4cf609cab8..67e9fb4f3f1fb 100644
--- a/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/Solution.cpp	
+++ b/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/Solution.cpp	
@@ -12,21 +12,20 @@
 class Solution {
 public:
     TreeNode* lcaDeepestLeaves(TreeNode* root) {
+        auto dfs = [&](this auto&& dfs, TreeNode* root) -> pair<TreeNode*, int> {
+            if (!root) {
+                return {nullptr, 0};
+            }
+            auto [l, d1] = dfs(root->left);
+            auto [r, d2] = dfs(root->right);
+            if (d1 > d2) {
+                return {l, d1 + 1};
+            }
+            if (d1 < d2) {
+                return {r, d2 + 1};
+            }
+            return {root, d1 + 1};
+        };
         return dfs(root).first;
     }
-
-    pair<TreeNode*, int> dfs(TreeNode* root) {
-        if (!root) {
-            return {nullptr, 0};
-        }
-        auto [l, d1] = dfs(root->left);
-        auto [r, d2] = dfs(root->right);
-        if (d1 > d2) {
-            return {l, d1 + 1};
-        }
-        if (d1 < d2) {
-            return {r, d2 + 1};
-        }
-        return {root, d1 + 1};
-    }
 };
\ No newline at end of file
diff --git a/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/Solution.cs b/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/Solution.cs
new file mode 100644
index 0000000000000..1667eef3fbeca
--- /dev/null
+++ b/solution/1100-1199/1123.Lowest Common Ancestor of Deepest Leaves/Solution.cs	
@@ -0,0 +1,37 @@
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     public int val;
+ *     public TreeNode left;
+ *     public TreeNode right;
+ *     public TreeNode(int val = 0, TreeNode left = null, TreeNode right = null) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+public class Solution {
+    public TreeNode LcaDeepestLeaves(TreeNode root) {
+        (TreeNode, int) Dfs(TreeNode root) {
+            if (root == null) {
+                return (null, 0);
+            }
+            
+            var l = Dfs(root.left);
+            var r = Dfs(root.right);
+            int d1 = l.Item2;
+            int d2 = r.Item2;
+
+            if (d1 > d2) {
+                return (l.Item1, d1 + 1);
+            }
+            if (d1 < d2) {
+                return (r.Item1, d2 + 1);
+            }
+            return (root, d1 + 1);
+        }
+
+        return Dfs(root).Item1;
+    }
+}