numbers_with_same_consecutive_differences.cpp

class Solution {
public:
    vector<int> ans;

    vector<int> numsSameConsecDiff(int n, int k) {
	    for(int i = 1; i < 10; i++)
		    genNum(n - 1, k, i, i);
	    return ans;
    }

    void genNum(int n, int& k, int sum, int last) {
	    if(n == 0) {
		    ans.push_back(sum);
		    return;
	    }
	    for(int i = 0; i < 10; i++) {
		    if(abs(i - last) == k) {
			    genNum(n - 1, k, sum * 10 + i, i);
		    }
	    }
    }
};