feat: add cs solution to lc problem: No.1846 (doocs#1970)

* feat: add cs solution to lc problem: No.1846

* Update README_EN.md to lc problem: No.1930

* Update README.md to lc problem: No.1846

Author: dev-mauli

solution/1800-1899/1846.Maximum Element After Decreasing and Rearranging/README.md

@@ -159,6 +159,22 @@ function maximumElementAfterDecrementingAndRearranging(arr: number[]): number {
 }
 ```
 
+### **C#**
+
+```cs
+public class Solution {
+    public int MaximumElementAfterDecrementingAndRearranging(int[] arr) {
+        Array.Sort(arr);
+        int n = arr.Length;
+        arr[0] = 1;
+        for (int i = 1; i < n; ++i) {
+            arr[i] = Math.Min(arr[i], arr[i - 1] + 1);
+        }
+        return arr[n - 1];
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1800-1899/1846.Maximum Element After Decreasing and Rearranging/README_EN.md

@@ -147,6 +147,22 @@ function maximumElementAfterDecrementingAndRearranging(arr: number[]): number {
 }
 ```
 
+### **C#**
+
+```cs
+public class Solution {
+    public int MaximumElementAfterDecrementingAndRearranging(int[] arr) {
+        Array.Sort(arr);
+        int n = arr.Length;
+        arr[0] = 1;
+        for (int i = 1; i < n; ++i) {
+            arr[i] = Math.Min(arr[i], arr[i - 1] + 1);
+        }
+        return arr[n - 1];
+    }
+}
+```
+
 ### **...**
 
 ```

solution/1800-1899/1846.Maximum Element After Decreasing and Rearranging/Solution.cs

@@ -0,0 +1,11 @@
+public class Solution {
+    public int MaximumElementAfterDecrementingAndRearranging(int[] arr) {
+        Array.Sort(arr);
+        int n = arr.Length;
+        arr[0] = 1;
+        for (int i = 1; i < n; ++i) {
+            arr[i] = Math.Min(arr[i], arr[i - 1] + 1);
+        }
+        return arr[n - 1];
+    }
+}