#2193
Minimum Number of Moves to Make Palindrome
candidate master · 1360 · lc hard +32 · verified · 52.7% accepted · 1,053 likes · top 43%
Description
You are given a string s consisting only of lowercase English letters.
In each move, you may swap any two adjacent characters.
Return the minimum number of moves needed to make s a palindrome.
The input is guaranteed to always be convertible to a palindrome.
Example 1:
Input: s = "aabb"
Output: 2
Explanation:
We can obtain two palindromes from s, "abba" and "baab".
- We can obtain "abba" from s in 2 moves: "aabb" -> "abab" -> "abba".
- We can obtain "baab" from s in 2 moves: "aabb" -> "abab" -> "baab".
Thus, the minimum number of moves needed to make s a palindrome is 2.
Example 2:
Input: s = "letelt"
Output: 2
Explanation:
One of the palindromes we can obtain from s in 2 moves is "lettel".
One of the ways we can obtain it is "letelt" -> "letetl" -> "lettel".
Other palindromes such as "tleelt" can also be obtained in 2 moves.
It can be shown that it is not possible to obtain a palindrome in less than 2 moves.
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