344. 反轉(zhuǎn)字符串

難度簡單750

編寫一個函數(shù)，其作用是將輸入的字符串反轉(zhuǎn)過來。輸入字符串以字符數(shù)組?s?的形式給出。

不要給另外的數(shù)組分配額外的空間，你必須原地修改輸入數(shù)組、使用 O(1) 的額外空間解決這一問題。

?

示例 1：

輸入：s = ["h","e","l","l","o"]輸出：["o","l","l","e","h"]

示例 2：

輸入：s = ["H","a","n","n","a","h"]輸出：["h","a","n","n","a","H"]

?

提示：

• 1 <= s.length <= 105

• s[i]?都是?ASCII?碼表中的可打印字符

通過次數(shù)725,608提交次數(shù)911,425

第一種對法：

雙指針法，時間復雜度O(n)

注意：記得迭代循環(huán)條件

class?Solution?{

public:

????void?reverseString(vector<char>&?s)?{

????????int?left,right;

????????left?=?0,right?=?s.size()-1;

????????while(left<right){

????????????char?tmp?=?s[left];

????????????s[left]?=?s[right];

????????????s[right]?=?tmp;

????????????left++,right--;

????????}

????}

};