diff --git a/C#/find-the-maximum-sum-of-node-values.cs b/C#/find-the-maximum-sum-of-node-values.cs
new file mode 100644
index 0000000..04f171f
--- /dev/null
+++ b/C#/find-the-maximum-sum-of-node-values.cs
@@ -0,0 +1,19 @@
+/** Time:  O(n) **/
+
+public class Solution {
+    public long MaximumValueSum(int[] nums, int k, int[][] edges)
+    {
+        long result = 0;
+        int diff = int.MaxValue;
+        int parity = 0;
+
+        foreach (var x in nums) {
+            var y = x ^ k;
+            result += Math.Max(x, y);
+            parity ^= x < y ? 1 : 0;
+            diff = Math.Min(diff, Math.Abs(x - y));
+        }
+
+        return result - parity * diff;
+    }
+}