# 旋转图像
给定一个 n × n 的二维矩阵 matrix 表示一个图像。请你将图像顺时针旋转 90 度。
你必须在 原地 旋转图像，这意味着你需要直接修改输入的二维矩阵。请不要 使用另一个矩阵来旋转图像。
示例 1：
输入：matrix = [[1,2,3],[4,5,6],[7,8,9]]
输出：[[7,4,1],[8,5,2],[9,6,3]]
示例 2：
输入：matrix = [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]]
输出：[[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]]
示例 3：
输入：matrix = [[1]]
输出：[[1]]
示例 4：
输入：matrix = [[1,2],[3,4]]
输出：[[3,1],[4,2]]
提示：
matrix.length == nmatrix[i].length == n1 <= n <= 20-1000 <= matrix[i][j] <= 1000
以下程序实现了这一功能，请你填补空白处内容：
```cpp
#include
using namespace std;
class Solution
{
public:
void rotate(vector> &matrix)
{
int size = matrix.size();
for (int i = 0; i < size / 2; i++)
{
int low = i, high = size - i - 1;
for (int j = low; j < high; j++)
{
int tmp = matrix[i][j];
_________________________;
}
}
}
};
```
## template
```cpp
#include
using namespace std;
class Solution
{
public:
void rotate(vector> &matrix)
{
int size = matrix.size();
for (int i = 0; i < size / 2; i++)
{
int low = i, high = size - i - 1;
for (int j = low; j < high; j++)
{
int tmp = matrix[i][j];
matrix[i][j] = matrix[size - 1 - j][i];
matrix[size - 1 - j][i] = matrix[size - 1 - i][size - 1 - j];
matrix[size - 1 - i][size - 1 - j] = matrix[j][size - 1 - i];
matrix[j][size - 1 - i] = tmp;
}
}
}
};
```
## 答案
```cpp
matrix[i][j] = matrix[size - 1 - j][i];
matrix[size - 1 - j][i] = matrix[size - 1 - i][size - 1 - j];
matrix[size - 1 - i][size - 1 - j] = matrix[j][size - 1 - i];
matrix[j][size - 1 - i] = tmp;
```
## 选项
### A
```cpp
matrix[i][j] = matrix[size - 1 - j][i];
matrix[size - 1 - j][i] = matrix[size - i][size - j];
matrix[size - 1 - i][size - j] = matrix[j][size - i];
matrix[j][size - 1 - i] = tmp;
```
### B
```cpp
matrix[i][j] = matrix[size - 1 - j][i];
matrix[size + 1 - j][i] = matrix[size + 1 - i][size + 1 - j];
matrix[size + 1 - i][size + 1 - j] = matrix[j][size + 1 - i];
matrix[j][size + 1 - i] = tmp;
```
### C
```cpp
matrix[i][j] = matrix[size - 1 - j][i];
matrix[size - 1 - j][i] = matrix[size - 1 - i][size + 1 - j];
matrix[size - 1 - i][size - 1 - j] = matrix[j][size + 1 - i];
matrix[j][size - 1 - i] = tmp;
```