一.题目要求

给你一个 m 行 n 列的矩阵 matrix ，请按照顺时针螺旋顺序 ，返回矩阵中的所有元素。

二.题目难度

中等

三.输入样例

示例 1：

输入：matrix = [[1,2,3],[4,5,6],[7,8,9]]
输出：[1,2,3,6,9,8,7,4,5]

示例 2：

输入：matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
输出：[1,2,3,4,8,12,11,10,9,5,6,7]

提示：
m == matrix.length
n == matrix[i].length
1 <= m, n <= 10
-100 <= matrix[i][j] <= 100

四.解题思路

找到四个方向坐标变化的规律遍历即可

五.代码实现

优化后

class Solution {
public:
    vector<int> spiralOrder(vector<vector<int>>& matrix) {

        vector<int> sup;
        int width = matrix.size();
        int length = matrix[0].size();

        
        int left = 0;
        int right = length - 1;
        int top = 0;
        int bottom = width - 1;

        while (left <= right && top <= bottom)
        {
          for (int i = left; i <= right; i++)
          {
              sup.push_back(matrix[top][i]);
          }
          top++;
          for (int i = top; i <= bottom; i++)
          {
             sup.push_back(matrix[i][right]);
          }
          right--;
          if (top <= bottom)
          {
            for (int i = right; i >= left; i--)
            {
                sup.push_back(matrix[bottom][i]);
            }
            bottom--;
          }

          if (left <= right)
          {
            for (int i = bottom; i >= top; i--)
           {
            sup.push_back(matrix[i][left]);
           }
            left++;
          }
          
        }

        return sup;
    }
};

优化前

class Solution {
public:
    vector<int> spiralOrder(vector<vector<int>>& matrix) {

        int wid = matrix.size();
        int len = matrix[0].size();

        int crtlen = len;
        int crtwid = wid;
        vector<int> ans;

        bool lefttoright = true;
        bool toptobottom = true;

        int lenindex = 0, widindex = 0, i;
        while (crtlen && crtwid)
        {
            if (lefttoright)
            {
                for (i = 0; i < crtlen; i++)
                {
                    ans.push_back(matrix[lenindex][widindex++]);
                }
                lenindex++; widindex--;
                lefttoright = !lefttoright;
                crtwid--;
            }
            else
            {
                for (i = 0; i < crtlen; i++)
                {
                    ans.push_back(matrix[lenindex][widindex--]);
                }
                lenindex--; widindex++;
                lefttoright = !lefttoright;
                crtwid--;
            }
            
            if (toptobottom)
            {
                for (i = 0; i < crtwid; i++)
                {
                    ans.push_back(matrix[lenindex++][widindex]);
                }
                widindex--; lenindex--;
                toptobottom = !toptobottom;
                crtlen--;
            }
            else
            {
                for (i = 0; i < crtwid; i++)
                {
                    ans.push_back(matrix[lenindex--][widindex]);
                }
                widindex++;lenindex++;
                toptobottom = !toptobottom;
                crtlen--;
            }

        }

        return ans;
    }
};

六.题目总结

注意溢出判断