> For the complete documentation index, see [llms.txt](https://dfine.gitbook.io/leetcode/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dfine.gitbook.io/leetcode/344.reverse_string.md).

# 344.Reverse String

**Reverse String**

难度:Easy

> 编写一个函数，其作用是将输入的字符串反转过来。输入字符串以字符数组 char\[] 的形式给出。 不要给另外的数组分配额外的空间，你必须原地修改输入数组、使用 O(1) 的额外空间解决这一问题。 你可以假设数组中的所有字符都是 ASCII 码表中的可打印字符。

```
示例 1：

输入：["h","e","l","l","o"]
输出：["o","l","l","e","h"]
示例 2：

输入：["H","a","n","n","a","h"]
输出：["h","a","n","n","a","H"]
```

代码如下：

```
class Solution {
public:
    void reverseString(vector<char>& s) {
        int len=s.size();
        for(int i=0;i<len/2;i++)
            swap(s[i],s[len-i-1]);
    }
};
```


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