<p>Given two integers n and k, return <em>an array of all the integers of length </em><code>n</code><em> where the difference between every two consecutive digits is </em><code>k</code>. You may return the answer in <strong>any order</strong>.</p>

<p>Note that the integers should not have leading zeros. Integers as <code>02</code> and <code>043</code> are not allowed.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> n = 3, k = 7
<strong>Output:</strong> [181,292,707,818,929]
<strong>Explanation:</strong> Note that 070 is not a valid number, because it has leading zeroes.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> n = 2, k = 1
<strong>Output:</strong> [10,12,21,23,32,34,43,45,54,56,65,67,76,78,87,89,98]
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>2 &lt;= n &lt;= 9</code></li>
	<li><code>0 &lt;= k &lt;= 9</code></li>
</ul>

class Solution {
public:
    void f1(int num, int n, int k, int c, vector<int> &st, vector<int> &ans)
{
    if (st.size() == n)
    {
        int value = 0;
        for (int i = 0; i < st.size(); i++)
        {
            if (i == st.size() - 1)
            {
                value = (st[i] + value);
            }
            else
            {
                value = (st[i] + value) * 10;
            }
        }
        ans.push_back(value);
        return;
    }
    if (0 <= num && num < 10)
    {
        int f = 0;
        if (num + k < 10)
        {
            st.push_back(num);
            f1(num + k, n, k, c + 1, st, ans);
            st.pop_back();
            f = 1;
        }
        if (f == 1 && c == n - 1)
        {
            return;
        }
        if (num - k >= 0 && num - k != num + k)
        {
            st.push_back(num);
            f1(num - k, n, k, c + 1, st, ans);
            st.pop_back();
        }
    }
    return;
}
    vector<int> numsSameConsecDiff(int n, int k) {
        vector<int> ans;
        vector<int> st;
        for (int i = 1; i < 10; i++) {
            f1(i, n, k, 0, st, ans);
        }
        return ans;
    }
};
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