求star

题目#

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 s 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。

示例 1：

输入：s = ["h","e","l","l","o"]
输出：["o","l","l","e","h"]

示例 2：

输入：s = ["H","a","n","n","a","h"]
输出：["h","a","n","n","a","H"]

提示：

• 1 <= s.length <= 105
• s[i] 都是 ASCII 码表中的可打印字符

解题:key:#

①双指针#

/**
 * @param {character[]} s
 * @return {void} Do not return anything, modify s in-place instead.
 */
var reverseString = function(s) {
    let left =0,right = s.length-1
    while(left < right) {
        [s[left],s[right]] = [s[right],s[left]]
        left++
        right--
    }
   
};

②取中值依次交换#

/**
 * @param {character[]} s
 * @return {void} Do not return anything, modify s in-place instead.
 */
var reverseString = function(s) {
    let len = s.length
    let half = Math.floor(len / 2)
    for(let i=0;i<half;i++){
        [s[i],s[len-1-i]] = [s[len-1-i],s[i]]
    }
   
};