Spiral print of 2D matrix

-
 class Solution
{
public:
    vector<int> spiralOrder(vector<vector<int>> &a)
    {
        vector<int> v;
        int sr = 0, er = a.size() - 1, sc = 0, 
                            ec = a[0].size() - 1, i;
        while (sr <= er && sc <= ec)
        {
            for (i = sc; i <= ec; i++)
                v.push_back(a[sr][i]);
            sr += 1;
            for (i = sr; i <= er; i++)
                v.push_back(a[i][ec]);
            ec -= 1;
            if (er >= sr)
            {
                for (i = ec; i >= sc; i--)
                    v.push_back(a[er][i]);
                er -= 1;
            }
            if (ec >= sc)
            {
                for (i = er; i >= sr; i--)
                    v.push_back(a[i][sc]);
                sc += 1;
            }
        }
        return v;
    }
};

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