Encode given string by shifting each character forward with its alphabetical value

Given string str of size N consisting of lowercase English alphabets, the task is to encode the given string as follows:

• change every character of that string to another character
• the distance between the changed character and the current character is the same as the distance between the current character and 'a'.
• Also, assume that the character's array forms a cycle, i.e. after 'z' the cycle starts again from 'a'.

Examples:

Input: str = "geeksforgeeks"
Output: "miiukkcimiiuk"
Explanation:
g changed to m (distance between g & a is 6, distance between m & g is 6)
e changed to i (distance between e & a is 4, distance between i & e is 4)
and same for other characters as well.

Input: str = "cycleofalphabet"
Output: "ewewickaweoacim"

Approach: This problem can be solved using the following steps:

• Run a loop from i=0 to i<N and traverse each character of the string. For each character str[i]:
  • Find the distance between str[i] and 'a', i.e. dist=str[i]-'a'.
  • Now, if (dist+(str[i]-'a')) > 26, this means that 'z' is exceeded, so
• Otherwise, change str[i] to str[i]+dist.
• Print the string as the answer to this problem.

Below is the implementation of the above approach:

ewewickaweoacim

Time Complexity: O(N)
Auxiliary Space: O(1)