LeetCode——加一

 

vector<int> plusOne(vector<int>& digits) {
        int length = digits.size();
        int focus = length - 1;
        
        digits[focus] += 1;
        while(digits[focus] == 10 & focus > 0)        //focus位是否进位
        {
            digits[focus] = 0;
            focus--;
            digits[focus] += 1;
        }
        if(digits[0] != 10)                      //0位是否为10
       //if(digits[focus] != 10)                 //逻辑相同 更快
        return digits;    
        else                                     //对应所有数值均为9.如[9,9,9,9]
        {
            vector<int> num{1};
            while(length--)
                num.push_back(0);
            return num;
        }
    }