CCF 201412-2 Z扫描 100分

int main()
{
    int n;
    cin >> n;
    vector<vector<int>>hehe(n, vector<int>(n, 0));
    for (int i = 0; i < n; ++i)
        for (int j = 0; j < n; ++j)
            cin >> hehe[i][j];
    vector<int>ans;
    int flag = -1;
    for (int i = 0; i < n; ++i)
    {
        int tmp = i;
        if (flag==1)
            while (tmp >= 0)
            {
                ans.push_back(hehe[i - tmp][tmp]);
                tmp--;
            }
        else
            while (tmp >= 0)
            {
                ans.push_back(hehe[tmp][i - tmp]);
                tmp--;
            }
        flag = -flag;
    }
    for (int i =  1; i<n; i++)
    {
        int tmp = i;
        if (flag==1)
            while (tmp < n)
            {
                ans.push_back(hehe[tmp][n + i - 1 - tmp]);
                tmp++;
            }
        else
            while (tmp < n)
            {
                ans.push_back(hehe[n + i - 1 - tmp][tmp]);
                tmp++;
            }
        flag = -flag;
    }
    for (auto i : ans)
        cout << i << " ";
}int main()
{
    int n;
    cin >> n;
    vecto