Update 0059.螺旋矩阵II.md

problems/0059.螺旋矩阵II.md

@@ -598,5 +598,30 @@ object Solution {
   }
 }
 ```
+C#：
+```csharp
+public class Solution {
+    public int[][] GenerateMatrix(int n) {
+        int[][] answer = new int[n][];
+        for(int i = 0; i < n; i++)
+            answer[i] = new int[n];
+        int start = 0;
+        int end = n - 1;
+        int tmp = 1;
+        while(tmp < n * n)
+        {
+            for(int i = start; i < end; i++) answer[start][i] = tmp++;
+            for(int i = start; i < end; i++) answer[i][end] = tmp++;
+            for(int i = end; i > start; i--) answer[end][i] = tmp++;
+            for(int i = end; i > start; i--) answer[i][start] = tmp++;
+            start++;
+            end--;
+        }
+        if(n % 2 == 1) answer[n / 2][n / 2] = tmp;
+        return answer;
+    }
+}
+```
+
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