HackerRank: The Love-Letter Mystery

Problem

James found a love letter his friend Harry has written for his girlfriend. James is a prankster, so he decides to meddle with the letter. He changes all the words in the letter into palindromes.

To do this, he follows two rules:

  1. He can reduce the value of a letter, e.g. he can change d to c, but he cannot change c to d.
  2. In order to form a palindrome, if he has to repeatedly reduce the value of a letter, he can do it until the letter becomes a. Once a letter has been changed to a, it can no longer be changed.

Each reduction in the value of any letter is counted as a single operation. Find the minimum number of operations required to convert a given string into a palindrome.

Input Format

The first line contains an integer T, i.e., the number of test cases.
The next T lines will contain a string each. The strings do not contain any spaces.

Constraints
1T10
1 length of string 10^4
All characters are lower case English letters.

Output Format

A single line containing the number of minimum operations corresponding to each test case.

Sample Input

4
abc
abcba
abcd
cba

Sample Output

2
0
4
2

Explanation

  1. For the first test case, abc -> abb -> aba.
  2. For the second test case, abcba is already a palindromic string.
  3. For the third test case, abcd -> abcc -> abcb -> abca = abca -> abba.
  4. For the fourth test case, cba -> bba -> aba.

Solution