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Description:

The array-form of an integer num is an array representing its digits in left to right order.

For example, for num = 1321, the array form is [1,3,2,1].
Given num, the array-form of an integer, and an integer k, return the array-form of the integer num + k.

Example 1:

Input: num = [1,2,0,0], k = 34
Output: [1,2,3,4]
Explanation: 1200 + 34 = 1234
Example 2:

Input: num = [2,7,4], k = 181
Output: [4,5,5]
Explanation: 274 + 181 = 455
Example 3:

Input: num = [2,1,5], k = 806
Output: [1,0,2,1]
Explanation: 215 + 806 = 1021

Constraints:

1 <= num.length <= 104
0 <= num[i] <= 9
num does not contain any leading zeros except for the zero itself.

1 <= k <= 104

Solution:

class Solution { public: vector<int> addToArrayForm(vector<int>& num, int k) { for (int i = num.size() - 1; i >= 0; --i) { num[i] += k; k = num[i] / 10; num[i] %= 10; } while (k > 0) { num.insert(begin(num), k % 10); k /= 10; } return num; } }; 

leetcode

challenge

Here is the link for the problem:
https://leetcode.com/problems/add-to-array-form-of-integer/