# 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);` `    `  `    ``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)

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