Algorithm Of Swift -- 2.字符串反转

题目描述：

        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"]

解法1：
func reverseString(_ s: inout [Character]) {
    var left = 0
    var right = s.count - 1

    while left < right {
        let temp = s[left]
        s[left] = s[right]
        s[right] = temp
        left += 1
        right -= 1
    }
}