<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 {
    vector<int>out;
    void helper(string data, const int n, const int k, int j){
        if (data.size() == n){
            if (out.empty() || stoi(data) != out.back()){
                out.push_back(stoi(data)); 
            }
            return;
        }

        for (int i{j+1}; i < n; ++i){
            if (data[i-1]-k >= '0'){
                helper(data+(char(data[i-1]-k)), n, k, i);
            }
            if (data[i-1]+k <= '9'){
                helper(data+(char(data[i-1]+k)), n, k, i);
            }
        }
    }
public:
    vector<int> numsSameConsecDiff(int n, int k) {
        string data{"1"};
        
        for (int i{}; i < 9; ++i){
            helper(data, n, k, 0);
            ++data[0];
        }

        return out;
    }
};
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