#P15896. [TOPC 2025] Palindromic Distance
[TOPC 2025] Palindromic Distance
Description
The edit distance between two strings and is the minimum number of edit operations that turns into . There are three edit operations that can be applied to a string: Insert a character, delete a character, and substitute some character by a different one.
For example, we can turn hello into world with four substitutions, so the edit distance is at most 4. You can turn wally into walter with two substitutions and one insertion, so the edit distance is at most 3. Computing the edit distance between two strings is a well-known problem with many applications.
The task at hand is to compute the edit distance of a string to one of the closest palindromes. A palindrome is a string that is the same when read backwards, for example madam.
The edit distance of hello to the closest palindrome is only 2: We can turn hello into ollo, or hllh, or ellle with two edit operations.
Write a program that can find the distance of a word to a closest palindrome.
Input Format
Each test contains multiple test cases. The first line contains the number of test cases . The description of the test cases follows.
The only line of each test case contains a word consisting only of lowercase letters.
Output Format
For each test case, output the edit distance of the input word to its closest palindrome.
6
aaaaba
hello
palindrome
abba
x
bababac
1
2
5
0
0
1
Hint
- The word has length at least one.
- It is guaranteed that the sum of the lengths of the words over all test cases does not exceed .
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