https://leetcode.com/problems/plus-one/
class Solution { public: vector<int> plusOne(vector<int>& digits) { int length=digits.size(); digits[length-1]=digits[length-1]+1; for (int i=digits.size()-1; i>0; i-- ) { if (digits[i]>9) { digits[i]=digits[i]-10; digits[i-1]=digits[i-1]+1; } } if (digits[0]>=10) { digits[0]=digits[0]; digits.push_back(0); for (int i=digits.size()-1; i>0; i-- ) { digits[i]=digits[i-1]; } digits[0]=1; } return digits; } };