LeetCode54 Spiral Matrix

题目：

Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order.

For example,
Given the following matrix:

[

 [ 1, 2, 3 ],

 [ 4, 5, 6 ],

 [ 7, 8, 9 ]

]

You should return [1,2,3,6,9,8,7,4,5]. （Medium）

分析：

题目没有什么复杂的算法要应用，就是一行一列输出，处理好细节即可。

比较清晰的写法是搞一个rowBegin, rowEnd, colBegin, colEnd，并在处理完一行/一列后更新值，并判断是否仍然满足 rowBegin <= rowEnd && colBegin <= colEnd

代码：

 class Solution {

 public:

     vector<int> spiralOrder(vector<vector<int>>& matrix) {

         vector<int> result;

         if (matrix.size() == ) {

             return result;

         }

         int m = matrix.size(), n = matrix[].size();

         int rowBegin = , rowEnd = m - , colBegin = , colEnd = n - ;

         while (rowBegin <= rowEnd && colBegin <= colEnd) {

             for (int i = colBegin; i <= colEnd; ++i ) {

                 result.push_back(matrix[rowBegin][i]);

             }

             rowBegin++;

             if (rowBegin > rowEnd) {

                 break;

             }

             for (int i = rowBegin; i <= rowEnd; ++i) {

                 result.push_back(matrix[i][colEnd]);

             }

             colEnd--;

             if (colBegin > colEnd) {

                 break;

             }

             for (int i = colEnd; i >= colBegin; --i) {

                 result.push_back(matrix[rowEnd][i]);

             }

             rowEnd--;

             if (rowBegin > rowEnd) {

                 break;

             }

             for (int i = rowEnd; i>= rowBegin; --i) {

                 result.push_back(matrix[i][colBegin]);

             }

             colBegin++;

         }

         return result;

     }

 };

巴特西

LeetCode54 Spiral Matrix

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