Given a string str consisting of lowercase letters only and an integer k, the task is to replace every character of the given string by character whose ASCII value is k times more than it. If ASCII value exceeds ‘z’, then start checking from ‘a’ in a cyclic manner.
Examples:
Input: str = “abc”, k = 2
Output: cde
a is moved by 2 times which results in character c
b is moved by 2 times which results in character d
c is moved by 2 times which results in character eInput: str = “abc”, k = 28
Output: cde
a is moved 25 times, z is reached. Then 26th character will be a, 27-th b and 28-th c.
b is moved 24 times, z is reached. 28-th is d.
b is moved 23 times, z is reached. 28-th is e.
Approach: Iterate for every character in the string and perform the below steps for each character:
- Add k to the ASCII value of character str[i].
- If it exceeds 122, then perform a modulus operation of k with 26 to reduce the number of steps, as 26 is the maximum number of shifts that can be performed in a rotation.
- To find the character, add k to 96. Hence the character with ASCII value k+96 will be the new character.
Repeat the above steps for every character of the given string.
Below is the implementation of the above approach:
C++
// CPP program to move every character // K times ahead in a given string #include <bits/stdc++.h> using namespace std; // Function to move string character void encode(string s,int k){ // changed string string newS; // iterate for every characters for(int i=0; i<s.length(); ++i) { // ASCII value int val = int(s[i]); // store the duplicate int dup = k; // if k-th ahead character exceed 'z' if(val + k > 122){ k -= (122-val); k = k % 26; newS += char(96 + k); } else newS += char(val + k); k = dup; } // print the new string cout<<newS; } // driver code int main(){ string str = "abc"; int k = 28; // function call encode(str, k); return 0; } // This code is contributed by Sanjit_Prasad |
Java
// Java program to move every character // K times ahead in a given string class GFG { // Function to move string character static void encode(String s, int k) { // changed string String newS = ""; // iterate for every characters for (int i = 0; i < s.length(); ++i) { // ASCII value int val = s.charAt(i); // store the duplicate int dup = k; // if k-th ahead character exceed 'z' if (val + k > 122) { k -= (122 - val); k = k % 26; newS += (char)(96 + k); } else { newS += (char)(val + k); } k = dup; } // print the new string System.out.println(newS); } // Driver Code public static void main(String[] args) { String str = "abc"; int k = 28; // function call encode(str, k); } } // This code is contributed by Rajput-JI |
Python3
# Python program to move every character # K times ahead in a given string # Function to move string character def encode(s, k): # changed string newS = "" # iterate for every characters for i in range(len(s)): # ASCII value val = ord(s[i]) # store the duplicate dup = k # if k-th ahead character exceed 'z' if val + k>122: k -= (122-val) k = k % 26 newS += chr(96 + k) else: newS += chr(val + k) k = dup # print the new string print (newS) # driver code str = "abc"k = 28 encode(str, k) |
C#
// C# program to move every character // K times ahead in a given string using System; public class GFG { // Function to move string character static void encode(String s, int k) { // changed string String newS = ""; // iterate for every characters for (int i = 0; i < s.Length; ++i) { // ASCII value int val = s[i]; // store the duplicate int dup = k; // if k-th ahead character exceed 'z' if (val + k > 122) { k -= (122 - val); k = k % 26; newS += (char)(96 + k); } else { newS += (char)(96 + k); } k = dup; } // print the new string Console.Write(newS); } // Driver Code public static void Main() { String str = "abc"; int k = 28; // function call encode(str, k); } } // This code is contributed by Rajput-JI |
PHP
<?php // PHP program to move every character // K times ahead in a given string // Function to move string character function encode($s, $k) { // changed string $newS = ""; // iterate for every characters for($i = 0; $i < strlen($s); ++$i) { // ASCII value $val = ord($s[$i]); // store the duplicate $dup = $k; // if k-th ahead character exceed 'z' if($val + $k > 122) { $k -= (122 - $val); $k = $k % 26; $newS = $newS.chr(96 + $k); } else $newS = $newS.chr($val + $k); $k = $dup; } // print the new string echo $newS; } // Driver code $str = "abc"; $k = 28; // function call encode($str, $k); // This code is contributed by ita_c ?> |
Output:
cde
Time Complexity: O(N), where N is the length of the string.
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