[leetcode] 344 reverse string

Write a function , Its function is to invert the input string . Input string as character array s Given in the form of .

Do not allocate extra space to another array , You have to modify the input array in place 、 Use O(1) To solve this problem .

Example 1：

Input ： s = [“h”,“e”,“l”,“l”,“o”]
Output ： [“o”,“l”,“l”,“e”,“h”]

Example 2：

Input ： s = [“H”,“a”,“n”,“n”,“a”,“h”]
Output ： [“h”,“a”,“n”,“n”,“a”,“H”]

Tips ：

• 1 <= s.length <= 105
• s[i] All are ASCII Printable characters in code table

# utilize python Direct inversion of sequence characteristics 
class Solution(object):
    def reverseString(self, s):
        s[:]=s[::-1]

# Double pointer 
class Solution(object):
    def reverseString(self, s):
        left = 0
        right = len(s)-1
        while left<right:
            tmp = s[left]
            s[left] = s[right]
            s[right] = tmp
            left+=1
            right-=1