LeetCode 54. Spiral Matrix

LeetCode 54. Spiral Matrix

循环输出矩阵元素，中等难度题目，查数要认真。
Solution1：我的答案

class Solution {
public:
    vector<int> spiralOrder(vector<vector<int>>& matrix) {
        if (!matrix.size() || !matrix[0].size()) return {};
        int m = matrix.size(), n = matrix[0].size();
        vector<int> res;
        int row_lower = 0, row_upper = m - 1, col_lower = 0, col_upper = n - 1, index = 0;
        while (row_lower <= row_upper && col_lower <= col_upper) {

            if (row_lower == row_upper) { //只剩下一行
                for (int i = index; i < n - index; i++)
                    res.push_back(matrix[row_lower][i]);
                break;
            } else if (col_lower == col_upper) { //只剩下一列
                for (int i = index; i < m - index; i++)
                    res.push_back(matrix[i][col_upper]);
                break;
            }
            else {//四个for循环做遍历读入数据
                for (int i = index; i < n - 1 - index; i++)
                    res.push_back(matrix[row_lower][i]);
                for (int i = index; i < m - 1 - index; i++)
                    res.push_back(matrix[i][col_upper]);
                for (int i = n - 1 - index; i > index; i--)
                    res.push_back(matrix[row_upper][i]);
                for (int i = m - 1 - index; i > index; i--)
                    res.push_back(matrix[i][col_lower]);
            }
            index++;
            row_lower++;row_upper--;
            col_lower++;col_upper--;
        }
        return res;
    }
};