Plus One (LeetCode) | Interview Question Explanation

PlusOne.cpp

class Solution {
public:
    vector<int> plusOne(vector<int>& digits) {
        digits.back()++;
        for(int i = digits.size() - 1; i > 0 && digits[i] == 10; --i) {
            digits[i] = 0;
            digits[i - 1]++;
        }
        
        if(digits[0] == 10) {
            digits[0] = 0;
            digits.insert(digits.begin(), 1);
        }
        return digits;
    }
};