345 Reverse Vowels of a String 1

Joel Castillo Espinosa 2

DESCRIPTION

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.

Examples

  • Example 1:
    • Input: s = “IceCreAm”
    • Output: “AceCreIm”
    • Explanation: The vowels in s are [‘I’, ‘e’, ‘e’, ‘A’]. On reversing the vowels, s becomes “AceCreIm”.
  • Example 2:
    • Input: s = “leetcode”
    • Output: “leotcede”

Constraints:

  • 1 ≤ s.length ≤ 3 * $10^5$
  • s consist of printable ASCII characters.

SOLUTION 3

string_reverse <- function(s){
  # split the string
  s_split <- strsplit(s, split = "") 
  
  #get the vowels
  i_vowel <- grep(s_split[[1]], pattern = "[aeiouAEIOU]")
  
  # reverse of vowels 
  i_vowel_rev <- rev(i_vowel)
  
  # reverse the vowels in the string
  s_rev <- s_split
  for (i in 1:length(i_vowel)) {
    i_normal <- i_vowel[i]
    i_rev <- i_vowel_rev[i]
    s_rev[[1]][i_normal] <- s_split[[1]][i_rev] 
  }
  result <- paste(s_rev[[1]],collapse = "")
  return(result)

}

Examples using the function

We can use the examples presented before.

string_reverse("IceCreAm")

## [1] "AceCreIm"

string_reverse(s = "leetcode")

## [1] "leotcede"

  1. This problem is originally from LeetCode, you can find it in Leetcode. ↩

  2. Email: jocastillo@colmex.mx. For more content visit my website: https://joelcastillo.netlify.app
    If you have any questions or suggestions, I’d be grateful to hear from you. ↩

  3. This solution is entirely my own work. It was developed using R version 4.4.1 (2024-06-14 ucrt). ↩