> For the complete documentation index, see [llms.txt](https://jenhsuan.gitbook.io/algorithm/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jenhsuan.gitbook.io/algorithm/leetcode/66.-plus-one.md).

# 66. Plus One

## 1.問題

* 給予一個list, 並在最末的數值+ 1, 問最終的list

![](/files/-LN9jB79b2L4DyriYVst)

## 2.想法

* 提問: 確定是在第一個元素還是最末個元素+ 1
* function header, parameter
* test input
* 說明想法 
  * 因為在第一個元素+ 1會比較簡單, 因此計算前先對vector reverse以方便計算
  * 計算時須注意新的值是(carry + 自己) % 10, 並且更新carry
  * 當結束計算, carry不為零時, push到list中
  * reverse回來
* 測試計算複雜度

## 3.程式碼

```
class Solution {
public:
    vector<int> plusOne(vector<int>& digits) {
        //vector<int> res;
        reverse(digits.begin(), digits.end());
        int ret = 0, curr = 0; 
        for (int i = 0 ; i < digits.size(); i++){
            if( i == 0){
                ret = (digits[0] + 1) / 10;
                digits[0] = ((digits[0] + 1) < 10) ? digits[0] + 1 : (digits[0] + 1) % 10;
            }else{
                int t = digits[i];
                digits[i] = ((digits[i] + ret) < 10) ? digits[i] + ret : (digits[i] + ret) % 10;
                ret = (ret + t) / 10;
            }
        }
        if(ret != 0){
            digits.push_back(ret);
        }
        reverse(digits.begin(), digits.end());
        return digits;
    }
};
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://jenhsuan.gitbook.io/algorithm/leetcode/66.-plus-one.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.