Given a string str containing only alphabets, the task is to print the longest subsequence of the string str containing only vowels.
Examples:
Input: str = “neveropen”
Output: eeoee
Explanation:
“eeoee” is the longest subsequence of the string containing only vowels.
Input: str = “HelloWorld”
Output: eoo
Explanation:
“eeo” is the longest subsequence of the string containing only vowels.
Approach:
- Traverse through the given string character by character.
- If the character is a vowel, append it to the resultant string.
- When the traversal completes, the required longest subsequence containing only vowels is stored in the resultant string.
Below is the implementation of the above approach:
C++
// C++ program to find the longest// subsequence containing only vowels#include <bits/stdc++.h>using namespace std;// Function to check whether// a character is vowel or notbool isVowel(char x){ x = tolower(x); // Returns true if x is vowel return (x == 'a' || x == 'e' || x == 'i' || x == 'o' || x == 'u');}// Function to find the longest subsequence// which contain all vowelsstring longestVowelSubsequence(string str){ string answer = ""; // Length of the string int n = str.size(); // Iterating through the string for (int i = 0; i < n; i++) { // Checking if the character is a // vowel or not if (isVowel(str[i])) { // If it is a vowel, then add it // to the final string answer += str[i]; } } return answer;}// Driver codeint main(){ string str = "neveropen"; cout << longestVowelSubsequence(str) << endl; return 0;} |
Java
// Java program to find the longest// subsequence containing only vowelsclass GFG{ // Function to check whether// a character is vowel or notstatic boolean isVowel(char x){ x = Character.toLowerCase(x); // Returns true if x is vowel return (x == 'a' || x == 'e' || x == 'i' || x == 'o' || x == 'u');} // Function to find the longest subsequence// which contain all vowelsstatic String longestVowelSubsequence(String str){ String answer = ""; // Length of the String int n = str.length(); // Iterating through the String for (int i = 0; i < n; i++) { // Checking if the character is a // vowel or not if (isVowel(str.charAt(i))) { // If it is a vowel, then add it // to the final String answer += str.charAt(i); } } return answer;} // Driver codepublic static void main(String[] args){ String str = "neveropen"; System.out.print(longestVowelSubsequence(str) +"\n");}}// This code is contributed by 29AjayKumar |
Python 3
# Python 3 program to find the longest# subsequence containing only vowels# Function to check whether# a character is vowel or notdef isVowel(x): # Returns true if x is vowel return (x == 'a' or x == 'e'or x == 'i' or x == 'o' or x == 'u') # Function to find the longest subsequence# which contain all vowelsdef longestVowelSubsequence(str): answer = "" # Length of the string n = len(str) # Iterating through the string for i in range(n): # Checking if the character is a # vowel or not if (isVowel(str[i])): # If it is a vowel, then add it # to the final string answer += str[i] return answer# Driver codestr = "neveropen"print(longestVowelSubsequence(str))# This code is contributed by apurva raj |
C#
// C# program to find the longest// subsequence containing only vowelsusing System;class GFG{ // Function to check whether// a character is vowel or notstatic bool isVowel(char x){ x = char.ToLower(x); // Returns true if x is vowel return (x == 'a' || x == 'e' || x == 'i' || x == 'o' || x == 'u');} // Function to find the longest subsequence// which contain all vowelsstatic String longestVowelSubsequence(String str){ String answer = ""; // Length of the String int n = str.Length; // Iterating through the String for (int i = 0; i < n; i++) { // Checking if the character is a // vowel or not if (isVowel(str[i])) { // If it is a vowel, then add it // to the readonly String answer += str[i]; } } return answer;} // Driver codepublic static void Main(String[] args){ String str = "neveropen"; Console.Write(longestVowelSubsequence(str)+"\n");}}// This code is contributed by Princi Singh |
Javascript
<script>// Javascript program to find the longest// subsequence containing only vowels// Function to check whether// a character is vowel or notfunction isVowel(x){ x = (x.toLowerCase()); // Returns true if x is vowel return (x == 'a' || x == 'e' || x == 'i' || x == 'o' || x == 'u');}// Function to find the longest subsequence// which contain all vowelsfunction longestVowelSubsequence(str){ var answer = ""; // Length of the string var n = str.length; // Iterating through the string for (var i = 0; i < n; i++) { // Checking if the character is a // vowel or not if (isVowel(str[i])) { // If it is a vowel, then add it // to the final string answer += str[i]; } } return answer;}// Driver codevar str = "neveropen";document.write( longestVowelSubsequence(str));// This code is contributed by importantly.</script> |
Output:
eeoee
Time Complexity: O(N)
Auxiliary Space: O(N), The extra space is used to store the result.
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