<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 dfs(vector<int>& ans, int N, int& K, int num){
        if(N==0){
            ans.push_back(num);
            return ;
        }
        int digit = num%10;
        if(digit + K <=9){
            dfs(ans, N-1, K, num*10 + digit + K);            
        }
        // K!=0 is considered, as when K=0 then the above if condition produces same solution as the below condition. (Ex: N=2, K=0)
        if(digit - K >=0 && K!=0){
            dfs(ans, N-1, K, num*10 + digit - K);            
        }
       
    }
    vector<int> numsSameConsecDiff(int N, int K) {
        
        vector<int> ans;
        if(N==1) ans.push_back(0);
		// First digit will never be 0 except when N=1.
        for(int i=1;i<=9;i++){
            dfs(ans, N-1, K, i);
        }
        return ans;
        
    }
};
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