# 59. Spiral Matrix II

**<font color=red>难度:Medium<font>**

## 刷题内容
> 原题连接

* https://leetcode.com/problems/spiral-matrix-ii/

> 内容描述

```
Given a positive integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.

Example:

Input: 3
Output:
[
 [ 1, 2, 3 ],
 [ 8, 9, 4 ],
 [ 7, 6, 5 ]
]
```

> 思路1
******- 时间复杂度: O(n^2)******- 空间复杂度: O(n^2)******

和之前的旋转遍历矩阵一样的方法，只不过这里我们要先分配一个矩阵储存，因为vector数组不好操作。

```cpp
class Solution {
public:
    vector<vector<int>> generateMatrix(int n) {
        int temp[n][n];
        int range = n,cur = 1;
        for(int i = 0;i < (n + 1) / 2 ;++i)
        {
            for(int j = 0;j < range;++j)
                temp[i][j + i] = cur++;
            for(int j = 1;j < range;++j)
                temp[i + j][i + range - 1] = cur++;
            for(int j = 1;j < range;++j)
                temp[i + range - 1][range + i - 1 -j] = cur++;
            for(int j = 1;j < range - 1;++j)
                temp[range + i - 1 - j][i] = cur++;
            range -= 2;
        }
        vector<vector<int> > ans;
        for(int i = 0;i < n;++i)
        {
            vector<int> v;
            for(int j = 0;j < n;++j)
                v.push_back(temp[i][j]);
            ans.push_back(v);
        }
        return ans;
    }
};
```