[LeetCode] Plus One

Given a number represented as an array of digits, plus one to the number.

class Solution {

public:

    vector<int> plusOne(vector<int> &digits) {

        // IMPORTANT: Please reset any member data you declared, as

        // the same Solution instance will be reused for each test case.

        int a = 1;

        vector<int> ans;

        vector<int>::iterator it;

        for(int i = digits.size() - 1;i >= 0;i--)

        {

            it = ans.begin();

            int b = (a + digits[i]) % 10;

            a = (a + digits[i]) / 10;

            ans.insert(it, b);

        }

        if(a != 0)

        {

            it = ans.begin();

            ans.insert(it, a);

        }

        

        return ans;

    }

};