LeetCode 66:Plus One

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

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

//題意：一個整數按位存儲於一個int數組中，排列順序為：最高位在digits[0] ，最低位在digits[n-1]，
//例如：98，存儲為：digits[0]=9; digits[1]=8;
//解題思路:從數組的最後一位開始加1，需要考慮進位，如果到digits[0]位之後仍然有進位存在,則將進位加上
class Solution {
public:
    vector plusOne(vector &digits) {
        // IMPORTANT: Please reset any member data you declared, as
        // the same Solution instance will be reused for each test case.
        int a = 1;
        vector ans;
        vector::iterator it;
        for(int i = digits.size() - 1;i >= 0;i--)
        {
            it = ans.begin();
            int tmp = (a + digits[i]) % 10;
            a = (a + digits[i]) / 10;
            ans.insert(it, tmp);
        }
        if(a != 0)
        {
            it = ans.begin();
            ans.insert(it, a);
        }
        
        return ans;
    }
};