345. Voice letter in the reverse string

topic：

345. Voice letter in the reverse string.md

Thought：

Write two methods，Watch the reminder of the three leaves of the palace water，Can be made with dual pointers，See if both the elements of both ends are vowel letters。 Improved two editions。

Code：

Double pointer

class Solution:
    def reverseVowels(self, s: str) -> str:
        vowels = 'aeiouAEIOU'
        start = 0
        end = len(s) - 1
        while start < end:
            while s[end] not in vowels and start < end:
                end -= 1
            while s[start] not in vowels and start < end:
                start += 1
            if s[start] in vowels and s[end] in vowels:
                s[start], s[end] = s[end], s[start]
                start += 1
                end -= 1
        return ''.join(s)

String operation

class Solution:
    def reverseVowels(self, s: str) -> str:
        s = list(s)
        vowels = 'aeiouAEIOU'
        ans = []
        for i in s:
            if i in vowels:
                ans.append(i)
        a = ''
        for i in range(len(s)):
            if s[i] in vowels:
                a += ans.pop()
            else:
                a += s[i]
        return ''.join(a)