Problem

Given a string s, reverse only all the vowels in the string and return it.

The vowels are ‘a’, ‘e’, ‘i’, ‘o’, and ‘u’, and they can appear in both lower and upper cases, more than once.

Algorithm

Collect all the vowels and reverse the order, then relpace depend on the origional order.

Code

class Solution:def reverseVowels(self, s: str) -> str:vowels = []slen = len(s)for i in range(slen):if s[i] == 'a' or s[i] == 'e' or s[i] == 'i' or s[i] == 'o' or s[i] == 'u' or s[i] == 'A' or s[i] == 'E' or s[i] == 'I' or s[i] == 'O' or s[i] == 'U':vowels.append(s[i])vowels.reverse()j = 0ans = ""for i in range(slen):if s[i] == 'a' or s[i] == 'e' or s[i] == 'i' or s[i] == 'o' or s[i] == 'u' or s[i] == 'A' or s[i] == 'E' or s[i] == 'I' or s[i] == 'O' or s[i] == 'U':ans += vowels[j]j += 1else: ans += s[i]return ans