# Rearrange a string according to the given indices

Given a string S and an array index[], the task is to rearrange the string S by placing every character S[i] to position index[i].
Example

Input: S = “geeksforgeeks”, index[] = {5, 6, 7, 0, 1, 2, 8, 9, 10, 3, 4, 11, 12}
Output: ksfeegeeorgks
Input: S = “math”, index[] = {0, 1, 2, 3}
Output: math

Approach:
To solve the problem, follow the steps given below:

• Convert the string S to a list of characters, since strings are immutable in nature.
• Copy the list. Rearrange the characters in the this list according the values from index[i].
• Convert the list to string and print the final string.

Below is the implementation of the above approach:

## C++

 // C++ program to implement // the above approach #include using namespace std;   // Function to convert the strings // to proper void Convertstrings(string s, int index[],                               int n) {     char a[s.length()];     char b[s.length()];           // Convert string to array     for(int ii = 0; ii < s.length(); ii++)     {         a[ii] = s[ii];         b[ii] = s[ii];     }           int i = 0, j = 0;           // Move characters to specified indices     while(j < s.length() && i < n)     {         int k = index[i];         int temp = a[j];         b[k] = temp;                   j += 1;         i += 1;     }           string tmp = "";           // Convert the list to string     for(i = 0; i < s.length(); i++)     {         tmp += b[i];     }       // Print the answer     cout << tmp << endl; }   // Driver Code int main() {     string s = "geeksforgeeks";     int index[] = { 5, 6, 7, 0, 1, 2, 8,                     9, 10, 3, 4, 11, 12};           int n = sizeof(index) / sizeof(index[0]);           Convertstrings(s, index, n);     return 0; }   // This code is contributed by rutvik_56

## Java

 // Java program to implement // the above approach import java.util.*; class GFG{   // Function to convert the Strings // to proper static void ConvertStrings(char []s,                            int index[],                            int n) {     char []a = new char[s.length];     char []b = new char[s.length];           // Convert String to array     for(int ii = 0; ii < s.length; ii++)     {         a[ii] = s[ii];         b[ii] = s[ii];     }           int i = 0, j = 0;           // Move characters to specified indices     while(j < s.length && i < n)     {         int k = index[i];         int temp = a[j];         b[k] = (char) temp;                   j += 1;         i += 1;     }           String tmp = "";           // Convert the list to String     for(i = 0; i < s.length; i++)     {         tmp += b[i];     }       // Print the answer     System.out.print(tmp +"\n"); }   // Driver Code public static void main(String[] args) {     String s = "geeksforgeeks";     int index[] = { 5, 6, 7, 0, 1, 2, 8,                     9, 10, 3, 4, 11, 12};           int n = index.length;           ConvertStrings(s.toCharArray(), index, n); } }   // This code is contributed by Rohit_ranjan

## Python3

 # Python3 Program to implement # the above approach   # Function to convert the strings # to proper def Convertstrings(s, index):     a = []     j = 0     i = 0       # Convert string to list     for ii in str(s):         a.append(ii)       # Copy the list to another list     b = a[:]       # Move characters to specified indices     while j < len(a) and i < len(index):         k = index[i]         temp = a[j]         b[k] = temp         j += 1         i += 1     s = ''       # Convert the list to string     for i in range(len(b)):         s += b[i]       # Print the answer     print(s)     # Driver Code s = "geeksforgeeks" index = [5, 6, 7, 0, 1, 2, 8, 9, 10, 3, 4, 11, 12] Convertstrings(s, index)

## C#

 // C# program to implement // the above approach using System; class GFG{   // Function to convert the Strings // to proper static void ConvertStrings(char []s,                            int []index,                            int n) {     char []a = new char[s.Length];     char []b = new char[s.Length];           // Convert String to array     for(int ii = 0; ii < s.Length; ii++)     {         a[ii] = s[ii];         b[ii] = s[ii];     }           int i = 0, j = 0;           // Move characters to specified indices     while(j < s.Length && i < n)     {         int k = index[i];         int temp = a[j];         b[k] = (char) temp;                   j += 1;         i += 1;     }           String tmp = "";           // Convert the list to String     for(i = 0; i < s.Length; i++)     {         tmp += b[i];     }       // Print the answer     Console.Write(tmp +"\n"); }   // Driver Code public static void Main(String[] args) {     String s = "geeksforgeeks";     int []index = { 5, 6, 7, 0, 1, 2, 8,                     9, 10, 3, 4, 11, 12};           int n = index.Length;           ConvertStrings(s.ToCharArray(), index, n); } }   // This code is contributed by Rajput-Ji

Output:

ksfeegeeorgks

Time Complexity: O(N)
Auxiliary Space: O(N)

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.

My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

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.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Article Tags :
Practice Tags :

1

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