leetcode_gym/_problems/reverseVowelsFromAString.md

layout, title, last_solved, category, leetcode_url, status

layout	title	last_solved	category	leetcode_url	status
page	Reverse Vowels Of a String		string	https://leetcode.com/problems/reverse-vowels-of-a-string/submissions/	Solved

Problem

Write a function that takes a string as input and reverse only the vowels of a string.

Example 1:

Input: "hello"
Output: "holle"
Example 2:

Input: "leetcode"
Output: "leotcede"
Note:
The vowels does not include the letter "y".

Solution

Note:

• cannot swap characters in a string directly so change it to a list first and join them at the end

{% highlight python %}

def reverseVowels(self, s: str) -> str:

lst = list(s)

def isVowel(c):
    if c in "AEIOUaeiou":
        return True
    return False

def swap(x,y,lst):
    tmp = lst[x]
    lst[x]=s[y]
    lst[y]=tmp


left, right = 0, len(lst)-1


while left<right:
    
    # get left to vowel
    while not isVowel(lst[left]) and left<right:
        left+=1
    
    # get right to vowel
    while not isVowel(s[right]) and left<right:
        right-=1
    
    # swap
    swap(left, right, lst)
    
    # move pointers
    left+=1
    right-=1

return ''.join(lst)

{% endhighlight %}