leetcode之Reverse Vowels of a String

这题是典型的双指针问题，前后各一个指针用来检测是否是元音，都是的话互相交换来解决。

class Solution(object):
    def reverseVowels(self, s):
        """
        :type s: str
        :rtype: str
        """
        if len(s) < 2:
            return s
        i = 0
        j = len(s) - 1
        vowels = ['a', 'e', 'i', 'o', 'u']
        s1 = list(s)
        s = s.lower()
        while i < j:
            if s[i] not in vowels:
                i = i + 1
            if s[j] not in vowels:
                j = j - 1
            if i < j and s[i] in vowels and s[j] in vowels:
                s1[i], s1[j] = s1[j], s1[i]
                i = i + 1
                j = j - 1
        return ''.join(s1)

理论上leetcode的344. Reverse String也是同样的道理。不过我还是更喜欢return s[::-1]一句话来搞定。