66. Plus One

Given a non-negative integer represented as a non-empty array of digits, plus one to the integer.

You may assume the integer do not contain any leading zero, except the number 0 itself.

The digits are stored such that the most significant digit is at the head of the list.

 模拟加法

class Solution {
public:
    vector<int> plusOne(vector<int>& digits) {
        int n = digits.size();
        vector <int> w;
        digits[n - 1] += 1;
        if (digits[n - 1] >= 10){
            for (int i = n - 1; i >= 0; --i) {
                if(i > 0) digits[i - 1] += digits[i] / 10;
                else {
                    if (digits[0] / 10) w.push_back(digits[0] / 10);
                }
            }
        }
        else return digits;
        for (int i = 0; i < n; ++i) {
            w.push_back(digits[i] % 10);
        }
        return w;
    }
};

这里有一个其他人写的挺好看的代码

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