Alternate vowel and consonant string

Given a string, rearrange characters of the given string such that the vowels and consonants occupy alternate position. If string can not be rearranged in desired way, print “no such string”. The order of vowels with respect to each other and the order of consonants with respect to each other should be maintained.

If more than one required strings can be formed, print the lexicographically smaller.

Examples:

Input : geeks
Output : gekes

Input : onse
Output : nose
There are two possible outcomes
"nose" and "ones".  Since "nose"
is lexicographically smaller, we
print it.

Recommended: Please try your approach on {IDE} first, before moving on to the solution.

1. Count number of vowels and consonants in given string.
2. If difference between counts is more than one, return “Not Possible”.
3. If there are more vowels than consonants, print first vowel first and recur for remaining string.
4. If there are more consonants than vowels, print first consonant first and recur for remaining string.
5. If counts are same, compare first vowel with first consonant and print the smaller one first.

C++

 // C++ implementation of alternate vowel and // consonant string #include using namespace std;    // 'ch' is vowel or not bool isVowel(char ch) {     if (ch == 'a' || ch == 'e' || ch == 'i' ||             ch == 'o' || ch =='u')         return true;     return false; }    // create alternate vowel and consonant string // str1[0...l1-1] and str2[start...l2-1] string createAltStr(string str1, string str2,                     int start, int l) {     string finalStr = "";        // first adding character of vowel/consonant     // then adding character of consonant/vowel     for (int i=0, j=start; j= 2)         return "no such string";        // remove first character of vowel string     // then create alternate string with     // cstr[0...nc-1] and vstr[1...nv-1]     if (nv > nc)         return (vstr.at(0) + createAltStr(cstr, vstr, 1, nv));        // remove first character of consonant string     // then create alternate string with     // vstr[0...nv-1] and cstr[1...nc-1]     if (nc > nv)         return (cstr.at(0) + createAltStr(vstr, cstr, 1, nc));        // if both vowel and consonant     // strings are of equal length     // start creating string with consonant     if (cstr.at(0) < vstr.at(0))         return createAltStr(cstr, vstr, 0, nv);        // start creating string with vowel     return createAltStr(vstr, cstr, 0, nc); }    // Driver program to test above int main() {     string str = "geeks";     cout << findAltStr(str);     return 0; }

Java

 // Java implementation of alternate vowel and // consonant string import java.util.*;    class GFG {    // 'ch' is vowel or not static boolean isVowel(char ch) {     if (ch == 'a' || ch == 'e' || ch == 'i' ||             ch == 'o' || ch =='u')         return true;     return false; }    // create alternate vowel and consonant string // str1[0...l1-1] and str2[start...l2-1] static String createAltStr(String str1, String str2,                     int start, int l) {     String finalStr = "";        // first adding character of vowel/consonant     // then adding character of consonant/vowel     for (int i = 0, j = start; j < l; i++, j++)         finalStr = (finalStr + str1.charAt(i)) +                                     str2.charAt(j);     return finalStr; }    // function to find the required // alternate vowel and consonant string static String findAltStr(String str) {     int nv = 0, nc = 0;     String vstr = "", cstr = "";     int l = str.length();     for (int i = 0; i < l; i++)     {         char ch = str.charAt(i);            // count vowels and updaye vowel string         if (isVowel(ch))         {             nv++;             vstr = vstr + ch;         }            // count consonants and update consonant         // string         else         {             nc++;             cstr = cstr + ch;         }     }        // no such string can be formed     if (Math.abs(nv - nc) >= 2)         return "no such string";        // remove first character of vowel string     // then create alternate string with     // cstr[0...nc-1] and vstr[1...nv-1]     if (nv > nc)         return (vstr.charAt(0) + createAltStr(cstr, vstr, 1, nv));        // remove first character of consonant string     // then create alternate string with     // vstr[0...nv-1] and cstr[1...nc-1]     if (nc > nv)         return (cstr.charAt(0) + createAltStr(vstr, cstr, 1, nc));        // if both vowel and consonant     // strings are of equal length     // start creating string with consonant     if (cstr.charAt(0) < vstr.charAt(0))         return createAltStr(cstr, vstr, 0, nv);        // start creating string with vowel     return createAltStr(vstr, cstr, 0, nc); }    // Driver code public static void main(String args[]) {     String str = "geeks";     System.out.println(findAltStr(str)); } }    // This code is contributed by // Shashank_Sharma

Python 3

 # Python implementation of alternate vowel # and consonant string     # 'ch' is vowel or not  def isVowel(ch):     if(ch == 'a' or ch == 'e' or         ch == 'i' or ch == 'o' or         ch == 'u'):         return True     return False    # create alternate vowel and consonant string  # str1[0...l1-1] and str2[start...l2-1]  def createAltStr(str1, str2, start, l):     finalStr = ""     i = 0            # first adding character of vowel/consonant      # then adding character of consonant/vowel      for j in range(start, l):         finalStr = (finalStr + str1[i]) + str2[j]         i + 1        return finalStr    # function to find the required  # alternate vowel and consonant string  def findAltStr(str1):     nv = 0     nc = 0     vstr = ""     cstr = ""     l = len(str1)     for i in range(0, l):                    # count vowels and updaye vowel string          if(isVowel(str1[i])):             nv += 1             vstr = vstr + str1[i]                        # count consonants and update          # consonant string          else:             nc += 1             cstr = cstr + str1[i]                    # no such string can be formed     if(abs(nv - nc) >= 2):         return "no such string"            # remove first character of vowel string      # then create alternate string with      # cstr[0...nc-1] and vstr[1...nv-1]      if(nv > nc):         return (vstr[0] + createAltStr(cstr, vstr, 1, nv))            # remove first character of consonant string      # then create alternate string with      # vstr[0...nv-1] and cstr[1...nc-1]     if(nc > nv):         return (cstr[0] + createAltStr(vstr, cstr, 1, nc))            # if both vowel and consonant      # strings are of equal length      # start creating string with consonant      if(cstr[0] < vstr[0]):         return createAltStr(cstr, vstr, 0, nv)        return createAltStr(vstr, cstr, 0, nc)             # Driver Code if __name__ == "__main__":     str1 = "geeks"     print(findAltStr(str1))    # This code is contributed by Sairahul099

C#

 // C# implementation of alternate vowel and // consonant string using System;    class GFG {    // 'ch' is vowel or not static Boolean isVowel(char ch) {     if (ch == 'a' || ch == 'e' || ch == 'i' ||             ch == 'o' || ch =='u')         return true;     return false; }    // create alternate vowel and consonant string // str1[0...l1-1] and str2[start...l2-1] static String createAltStr(String str1, String str2,                     int start, int l) {     String finalStr = "";        // first adding character of vowel/consonant     // then adding character of consonant/vowel     for (int i = 0, j = start; j < l; i++, j++)         finalStr = (finalStr + str1[i]) +                                     str2[j];     return finalStr; }    // function to find the required // alternate vowel and consonant string static String findAltStr(String str) {     int nv = 0, nc = 0;     String vstr = "", cstr = "";     int l = str.Length;     for (int i = 0; i < l; i++)     {         char ch = str[i];            // count vowels and updaye vowel string         if (isVowel(ch))         {             nv++;             vstr = vstr + ch;         }            // count consonants and update consonant         // string         else         {             nc++;             cstr = cstr + ch;         }     }        // no such string can be formed     if (Math.Abs(nv - nc) >= 2)         return "no such string";        // remove first character of vowel string     // then create alternate string with     // cstr[0...nc-1] and vstr[1...nv-1]     if (nv > nc)         return (vstr[0] + createAltStr(cstr, vstr, 1, nv));        // remove first character of consonant string     // then create alternate string with     // vstr[0...nv-1] and cstr[1...nc-1]     if (nc > nv)         return (cstr[0] + createAltStr(vstr, cstr, 1, nc));        // if both vowel and consonant     // strings are of equal length     // start creating string with consonant     if (cstr[0] < vstr[0])         return createAltStr(cstr, vstr, 0, nv);        // start creating string with vowel     return createAltStr(vstr, cstr, 0, nc); }    // Driver code public static void Main(String []args) {     String str = "geeks";     Console.WriteLine(findAltStr(str)); } }    // This code is contributed by Princi Singh

Output:

gekes

Time Complexity: O(n), where ‘n’ the is length of the string

This article is contributed by Ayush Jauhari. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

My Personal Notes arrow_drop_up

Article Tags :
Practice Tags :

Be the First to upvote.

Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.