344.反转字符串

344.反转字符串

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"]

题解

采用双指针法

class Solution(object):
    def reverseString(self, s):
        """
        :type s: List[str]
        :rtype: None Do not return anything, modify s in-place instead.
        """
        # 双指针法, 第一个和最后交换
        left = 0
        right = len(s) - 1
        # 不用判断个数是奇数个和偶数个。直接采用 while 循环。每次循环 left +1, right -1
        while left < right:
            s[left], s[right] = s[right], s[left]
            left += 1
            right -= 1

func reverseString(s []byte)  {
	left := 0
	right := len(s) -1

	for left < right{
		s[left], s[right] = s[right], s[left]
		left +=1
		right -=1
	}
}

变体

总结

参考