[LeetCode]Plus One

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.

解題思路：
這道題倒是挺簡單的，但是我最開始沒有理解題意（我的英語不好啊），這道題的本意是用一個數組表示一個非負整數，如：[1,0,9]表示109。給這個數組進行加1操作。明白了這個，就容易多了。下面是代碼：

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

class Solution {
public:
    vector plusOne(vector &digits) {
        int len = digits.size();
        int* stack = new int[len+1];
        int top = 0;
        int over = 1;
        for(int i=len-1;i>=0; i--){
            int number = digits[i] + over;
            over = number/10;
            stack[top++] = number%10;
        }
        if(over>0){
            stack[top++] = over;
        }
        vector result;
        while(top>0){
            result.push_back(stack[--top]);
        }
        delete stack;
        return result;
    }
};