plus-one

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

easy~

class Solution {public:    vector<int> plusOne(vector<int> &digits) {        int len=digits.size();        if(len<=0)            return vector<int>{};        int sum=++digits[len-1];        if(sum<=9)            return digits;        int pos=1;        digits[len-1]=0;        int begin=len-2;        while(begin>=0){                digits[begin]+=pos;                if(digits[begin]<=9){                    pos=0;                    break;                }                else{                    pos=1;                    digits[begin]=0;                }                --begin;            }        if(pos==1)            digits.insert(digits.begin(),1);        return digits;    }};