class Solution {
public:
    void print(vector<vector<int>>& map, vector<int>& ans, int st1, int ed1, int st2, int ed2) {
        if (st1 > ed1 || st2 > ed2) return;
        if (st1 == ed1 && st2 == ed2) {
            ans.push_back(map[st1][ed1]);
            return;
        }
        if (st1 == ed1) {
            for (int i = st2; i <= ed2; i++) ans.push_back(map[i][ed1]);
            return;
        }
        if (st2 == ed2) {
            for (int i = st1; i <= ed1; i++) ans.push_back(map[st2][i]);
            return;
        }
        for (int i = st1; i <= ed1; i++) ans.push_back(map[st2][i]);
        for (int i = st2 + 1; i <= ed2; i++) ans.push_back(map[i][ed1]);
        for (int i = ed1 - 1; i >= st1; i--) ans.push_back(map[ed2][i]);
        for (int i = ed2 - 1; i >= st2 + 1; i--) ans.push_back(map[i][st1]);
        print(map, ans, st1 + 1, ed1 - 1, st2 + 1, ed2 - 1);
        return;
    }
    vector<int> printMatrix(vector<vector<int> > matrix) {
        int row = matrix.size();
        int col = matrix[0].size();
        vector<int> ans;
        print(matrix, ans, 0, col - 1, 0, row - 1 );
        return ans;
    }
};