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;
    }
};