LeetCode Spiral Matrix

class Solution {

    public:

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

                    vector<int> ret;

                    int cols = 0;

                    int rows = 0;

                    if (!(rows = matrix.size()) || !(cols = matrix[0].size())) {

                            return ret;

                    }

                    int left = 0, top = 0, right = cols - 1, bottom = rows - 1;

                    while (left <= right && top <= bottom) {

                        circle_walk(left, top, right, bottom, matrix, ret);

                        left++, top++, bottom--, right--;

                    }

                    return ret;

            }



            void circle_walk(int left, int top, int right, int bottom, vector<vector<int> >& map, vector<int>& path) {

                    int rows = 0;

                    if (map.size() < 1 || map[0].size() < 1) return;

                            

                    // top row

                    for (int i=left; i<=right; i++) {

                        path.push_back(map[top][i]);

                    }



                    // right col

                    for (int i=top+1; i<=bottom; i++) {

                        path.push_back(map[i][right]);

                    }



                    // bottom row

                    for (int i=right-1; bottom != top && i>=left; i--) {

                        path.push_back(map[bottom][i]);

                    }



                    // left col

                    for (int i=bottom-1; left != right && i>top; i--) {

                        path.push_back(map[i][left]);

                    }



            }

};

又隔了好久没有写了，水一发，准备测试数据还是必要的，比如只有一行的matrix，只有一列的matrix等，或许可以发现编码中的问题。

第二轮：

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].

题解简洁很多：

class Solution {

public:

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

        vector<int> res;

        

        int m = matrix.size();

        if (m == 0) {

            return res;

        }

        int n = matrix[0].size();

        

        int row = 0, col = -1;

        while(true) {

            for (int i=0; i<n; i++) res.push_back(matrix[row][++col]);

            if (--m == 0) break;

            for (int i=0; i<m; i++) res.push_back(matrix[++row][col]);

            if (--n == 0) break;

            for (int i=0; i<n; i++) res.push_back(matrix[row][--col]);

            if (--m == 0) break;

            for (int i=0; i<m; i++) res.push_back(matrix[--row][col]);

            if (--n == 0) break;

        }

        return res;

    }

};