Minimum Number of Operations to Make String Palindrome

Last Updated on July 24, 2023 by Mayank Dham

Palindrome string is a string which is the same on reading from the front side as well as on the rear side. Example of a palindrome string is “NAMAN” as we can see that on reading this string from both ends, we will get “NAMAN” as our output. Hence, the given string will be a palindrome string. From analyzing single characters to rearranging entire sequences, we will unravel diverse methodologies for crafting palindromes efficiently. These methods not only demonstrate the beauty of problem-solving in computer science but also hold practical implications in various real-world applications, including string manipulation, error correction, and data validation.

Minimum Number of Moves to Make Palindrome String

Given a string, you have to find the minimum number of moves to make palindrome string i.e. you have to change the ascii value of the character which is present in the string. Palindrome string is a string which is same after reversing it. You can Practice this Question, for understanding the concept to find minimum number of moves to make palindrome string.

String Palindrome Test Case

Input:
1
abcd

Output:
4

Explanation:
String 'abcd' can be converted into its palindrome if we convert : 

'a'->'d' or 'd'->'a'  which takes (ASCII(d) - ASCII(a)) steps i.e. 3 steps.

'b'->'c' or 'c'->'b' which takes (ASCII(b) - ASCII(c)) steps i.e. 1 step.

Hence the total number of steps is 4.

How to find number of moves to make palindrome?

1) Palindrome: A palindrome is a string that contains same characters from both ends. For example, nitin can be read same from both ends. Element at i^th index from the start and end side both are the same.

2) As we know palindromes contains same characters at i^th index and (len -i)^th index. So we iterate from 0 to middle of the string and compare all the characters if at some index characters are different, the string is not palindrome. If all the characters remain same, the string is palindrome.

3) If two characters are not same at i^th index and (len -i)^th index, we have to make them the same. We can make them same by adding the ASCII value of difference of both the character to the smaller character.

4) Finally we add the difference to our counter, the final value of the counter will be answer according to the fundamentals of data structures in c++.

Example: Number of moves to make palindrome

• Let’s assume given string is abcds and we check values from both ends one by one, and check their difference, we take positive difference value as our step.
• In 1^st iteration, we compare a from start and s from end, we can convert either a to s or s to a. Their ASCII value difference is 18, so our current step count is 18.
• In 2^nd iteration, we compare b from start and d from end, we can convert either b to d or d to b. Their ASCII value difference is 2, so our current step count is 20.
• As last element left is middle element,which is also a palindrome in it’s own, so we’ll skip that. Hence We get our final count as 20.

Solution to find minimum number of moves to make palindrome:

#include <stdio.h>
int main()
{
  int test;
  scanf("%d", &test);

  while(test--){

    char a[10000001];
    scanf("%s", a);

    int no_of_operations = 0;

    for(int i=0; i<strlen(a)/2; i++){
      no_of_operations += abs( a[strlen(a)-i-1] - a[i] );
    }

    printf("%d\n", no_of_operations);

  }
}

#include <bits/stdc++.h>
using namespace std;
int main()
{
  int test;
  cin>>test;

  while(test--){

    char a[10000001];
    cin>>a;

    int no_of_operations = 0;

    for(int i=0; i<strlen(a)/2; i++){
      no_of_operations += abs( a[strlen(a)-i-1] - a[i] );
    }

    cout<<no_of_operations<<endl;

  }
}

import java.util.*;
import java.io.*;
import java.lang.Math;
public class Main {
  public static void main(String args[]) throws IOException {

    Scanner sc= new Scanner(System.in);
    int test = sc.nextInt();
      while(test != 0){

        String a = sc.next();

        int no_of_operations = 0;

        for(int i=0; i

						 

for _ in range(int(input())):

    a = input()

    no_of_operations = 0

    for i in range(len(a)//2):
        no_of_operations += abs( ord(a[len(a)-i-1]) - ord(a[i]) )
    
    print(no_of_operations)

[forminator_quiz id=”936″]

Conclusion
From understanding the underlying mathematical patterns to devising ingenious algorithms, we have discovered diverse strategies that optimize the transformation process. Whether it’s manipulating single characters or rearranging entire sequences, each approach adds depth to our comprehension of palindrome creation, enabling us to achieve this feat with elegance and precision.

As we ventured into the world of palindromes, we’ve recognized the practical implications of this endeavor in real-world scenarios. From string manipulation in text processing to error correction in data validation, the knowledge gained here proves invaluable in diverse applications across various industries.

FAQ on Minimum Number of Moves to Make Palindrome String

Here are some FAQs on minimum number of moves to make palindrome string.

Q: What is a palindrome?
A: A palindrome is a sequence of characters, such as a word, phrase, or number, that reads the same backward as it does forward. For example, "level," "madam," and "121" are palindromes.

Q: What does "minimum number of moves to make a palindrome" mean?
A: The minimum number of moves to make a palindrome refers to the smallest number of operations required to transform a given sequence into a palindrome. These operations can include inserting, deleting, or rearranging characters in the sequence.

Q: Why is determining the minimum number of moves to make a palindrome important?
A: Calculating the minimum number of moves to make a palindrome is a crucial problem in computer science and algorithm design. It has practical applications in tasks like data validation, error correction, and string manipulation.

Q: What are some techniques to calculate the minimum number of moves?
A: There are several techniques to calculate the minimum number of moves to make a palindrome, including dynamic programming, recursive approaches, and analyzing the characteristics of palindromes.

Q: How can I apply the knowledge from this article in real-world scenarios?
A: The knowledge gained from understanding the minimum number of moves to make a palindrome can be applied in various scenarios. For example, it can be used in text processing, spell checking, error correction, data validation, and any situation where you need to transform a sequence into a palindrome efficiently.