k-th character of decrypted string Java

PROGRAM TO FIND THE K-TH CHARACTER OF DECRYPTED STRING

import java.util.*;

  

class MAIN

{

  

// Function to find K'th character in 

// Encoded String

static char encodedChar(char[] str, int k)

{

    int i, j;

  

    int n = str.length;

  

    // To store length of substring

    int len;

  

    // To store length of substring when

    // it is repeated

    int num;

  

    // To store frequency of substring

    int freq;

  

    i = 0;

  

    while (i < n) 

    {

        j = i;

        len = 0;

        freq = 0;

  

        // Find length of substring by

        // traversing the string until 

        // no digit is found.

        while (j < n && Character.isAlphabetic(str[j])) 

        {

            j++;

            len++;

        }

  

        // Find frequency of preceding substring.

        while (j < n && Character.isDigit(str[j]))

        {

            freq = freq * 10 + (str[j] - '0');

            j++;

        }

  

        // Find length of substring when

        // it is repeated.

        num = freq * len;

  

        // If length of repeated substring is less than

        // k then required character is present in next

        // substring. Subtract length of repeated

        // substring from k to keep account of number of

        // characters required to be visited.

        if (k > num)

        {

            k -= num;

            i = j;

        }

  

        // If length of repeated substring is

        // more or equal to k then required 

        // character lies in current substring.

        else 

        {

            k--;

            k %= len;

            return str[i + k];

        }

    }

  

    // This is for the case when there

    // are no repetition in string.

    // e.g. str="abced".

    return str[k - 1];

}

  

// Driver Code

public static void main(String[] args) 

{

    String str = "abced";

    int k = 4;

  

    System.out.println(encodedChar(str.toCharArray(), k));

}

}

OUTPUT

e

CREDITS: https://www.geeksforgeeks.org/find-k-th-character-of-decrypted-string-set-2/