Leetcode:66. Plus One

Description

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.

思路

• 没啥好说的，注意进位问题。

代码

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