Given a string str, the task is to encrypt and reverse the string. The string is encrypted by adding every character of the string with it’s index in the string i.e. if character‘a’ is at index 2 then the character in the updated string will be ‘a’ + 2 = ‘c’. Since value of string may go beyond 256, do the addition under modulo 256.
Examples:
Input: str = “geeks”
Output: wngfg
‘g’ + 0 = ‘g’
‘e’ + 1 = ‘f’
‘e’ + 2 = ‘g’
‘k’ + 3 = ‘n’
‘s’ + 4 = ‘w’
Input: str = “java”
Output: dxbj
Approach:
- Add every character of the string with its index within the same string.
- Reverse the string.
- Print the reversed string.
Below is the implementation of the above approach:
// C++ implementation of the approach #include <bits/stdc++.h> using namespace std;
// Function to return the encryptet string string getEncryptedString(string str) { // To build the encrypted string
string sb = "" ;
// Traverse the string in reverse
for ( int i = str.length() - 1; i >= 0; i--)
{
sb+=( char )(( int )str[i] + i) % 256;
}
// Return the encrypted string
return sb;
} // Driver code int main()
{ string str = "geeks" ;
cout<<getEncryptedString(str)<<endl;
return 0;
} // This code is contributed by mits |
// Java implementation of the approach public class HelloWorld {
// Function to return the encryptet string
static String getEncryptedString(String str)
{
// To build the encrypted string
StringBuilder sb = new StringBuilder( "" );
// Traverse the string in reverse
for ( int i = str.length() - 1 ; i >= 0 ; i--) {
sb.append( "" + ( char )((str.charAt(i) + i) % 256 ));
}
// Return the encrypted string
return sb.toString();
}
// Driver code
public static void main(String[] args)
{
String str = "geeks" ;
System.out.println(getEncryptedString(str));
}
} |
# Python3 implementation of the approach # Function to return the encryptet string def getEncryptedString( str ):
# To build the encrypted string
sb = "";
# Traverse the string in reverse
for i in range ( len ( str ) - 1 , - 1 , - 1 ):
sb + = chr (( ord ( str [i]) + i) % 256 );
# Return the encrypted string
return sb;
# Driver code str = "geeks" ;
print (getEncryptedString( str ));
# This code is contributed by mits |
// C# implementation of the approach using System;
using System.Text;
public class HelloWorld
{ // Function to return the encryptet string
static String getEncryptedString(String str)
{
// To build the encrypted string
StringBuilder sb = new StringBuilder( "" );
// Traverse the string in reverse
for ( int i = str.Length - 1; i >= 0; i--)
{
sb.Append( "" + ( char )((str[i] + i) % 256));
}
// Return the encrypted string
return sb.ToString();
}
// Driver code
public static void Main(String[] args)
{
String str = "geeks" ;
Console.WriteLine(getEncryptedString(str));
}
} // This code contributed by Rajput-Ji |
<?php // PHP implementation of the approach // Function to return the encryptet string function getEncryptedString( $str )
{ // To build the encrypted string
$sb = "" ;
// Traverse the string in reverse
for ( $i = strlen ( $str ) - 1; $i >= 0; $i --)
{
$sb .= chr ((ord( $str [ $i ]) + $i ) % 256);
}
// Return the encrypted string
return $sb ;
} // Driver code $str = "geeks" ;
print (getEncryptedString( $str ));
// This code is contributed by mits ?> |
<script> // javascript implementation of the approach // Function to return the encryptet string
function getEncryptedString( str)
{
// To build the encrypted string
sb = "" ;
// Traverse the string in reverse
for (i = str.length - 1; i >= 0; i--) {
sb+=( "" + String.fromCharCode((str.charCodeAt(i) + i) % 256));
}
// Return the encrypted string
return sb;
}
// Driver code
var str = "geeks" ;
document.write(getEncryptedString(str));
// This code is contributed by Rajput-Ji </script> |
wngfg
Time complexity: O(N) where N is length of given string
Auxiliary Space: O(1)