Algorithm
Problem Name: 345. Reverse Vowels of a String
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.
Example 1:
Input: s = "hello" Output: "holle"
Example 2:
Input: s = "leetcode" Output: "leotcede"
Constraints:
1 <= s.length <= 3 * 105sconsist of printable ASCII characters.
Code Examples
#1 Code Example with C Programming
Code -
C Programming
#define IS_VOWEL(C) ((C) == 'a' || (C) == 'A' || \
(C) == 'e' || (C) == 'E' || \
(C) == 'i' || (C) == 'I' || \
(C) == 'o' || (C) == 'O' || \
(C) == 'u' || (C) == 'U')
char* reverseVowels(char* s) {
char *a, *b;
if (!s || !*s) return s;
a = s;
b = &s[strlen(s) - 1];
while (a < b) {
if (IS_VOWEL(*a) && IS_VOWEL(*b)) {
// swap
*a = *a ^ *b;
*b = *a ^ *b;
*a = *a ^ *b;
a ++;
b --;
} else if (IS_VOWEL(*a)) {
b --;
} else if (IS_VOWEL(*b)) {
a ++;
} else {
a ++;
b --;
}
}
return s;
}
Input
s = "hello"
Output
"holle"
#2 Code Example with Java Programming
Code -
Java Programming
class Solution {
public String reverseVowels(String s) {
int left = 0;
int right = s.length() - 1;
String vowels = "aeiouAEIOU";
char[] chars = s.toCharArray();
while (left < right) {
int vowelIndexLeft = vowels.indexOf(chars[left]);
int vowelIndexRight = vowels.indexOf(chars[right]);
if (vowelIndexLeft != -1 && vowelIndexRight != -1) {
char temp = chars[left];
chars[left++] = chars[right];
chars[right--] = temp;
}
else if (vowelIndexRight == -1) {
right--;
}
else {
left++;
}
}
return String.valueOf(chars);
}
}
Input
s = "hello"
Output
"holle"
#3 Code Example with Javascript Programming
Code -
Javascript Programming
const reverseVowels = function(s) {
if(s == null || s === '') return ''
const arr = s.split('')
let p = 0
const len = s.length
let e = s.length - 1
const v = ['a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U']
while(p < e) {
while(v.indexOf(arr[p]) === -1 && p < e) p++
while(v.indexOf(arr[e]) === -1 && p < e) e--
const tmp = arr[p]
arr[p] = arr[e]
arr[e] = tmp
p++
e--
}
return arr.join(''>
};
Input
s = "leetcode"
Output
"leotcede"
#4 Code Example with Python Programming
Code -
Python Programming
class Solution:
def reverseVowels(self, s):
r = [c for c in s if c in "aeiouAEIOU"]
return "".join(c in "aeiouAEIOU" and r.pop() or c for c in s)
Input
s = "leetcode"
Output
"leotcede"
#5 Code Example with C# Programming
Code -
C# Programming
using System.Collections.Generic;
using System.Text;
namespace LeetCode
{
public class _0345_ReverseVowelsOfAString
{
public string ReverseVowels(string s)
{
var vowels = new HashSet < char>() { 'a', 'e', 'i', 'o', 'u', 'A', 'E', 'I', 'O', 'U' };
int i = 0, j = s.Length - 1;
var sb = new StringBuilder(s);
while (i < j)
{
while (i < s.Length && !vowels.Contains(sb[i]))
i++;
while (j >= 0 && !vowels.Contains(sb[j]))
j--;
if (i == s.Length) break;
if (j == -1) break;
if (i >= j) break;
var temp = sb[i];
sb[i] = sb[j];
sb[j] = temp;
i++;
j--;
}
return sb.ToString();
}
}
}
Input
s = "hello"
Output
"holle"