class Solution {
public:
    vector<int> spiralOrder(vector<vector<int>>& matrix) {
        if(matrix.size() == 0 && matrix[0].size() == 0){
            return {{}};
        }
        int left = 0, right = matrix[0].size()-1, top = 0, bottom = matrix.size()-1;
        vector<int>res;
        while(left <= right && top <= bottom){
            for(int i = left; i <= right; i++){
                res.push_back(matrix[top][i]);
            }
            for(int i = top+1; i <= bottom; i++){
                res.push_back(matrix[i][right]);
            }
            if(left < right && top < bottom){
                for(int i = right-1; i > left; i--){
                    res.push_back(matrix[bottom][i]);
                }
                for(int i = bottom; i > top; i--){
                    res.push_back(matrix[i][left]);
                }
            }
            left++;
            right--;
            top++;
            bottom--;
        }
        return res;


    }
};