You are given a string s consisting only of lowercase English letters.
In one move, you can select any two adjacent characters of s and swap them.
Return the minimum number of moves needed to make s a palindrome.
Note that the input will be generated such that s can always be converted to a palindrome.
\n
Example 1:
\n\n\nInput: s = "aabb"\nOutput: 2\nExplanation:\nWe can obtain two palindromes from s, "abba" and "baab". \n- We can obtain "abba" from s in 2 moves: "aabb" -> "abab" -> "abba".\n- We can obtain "baab" from s in 2 moves: "aabb" -> "abab" -> "baab".\nThus, the minimum number of moves needed to make s a palindrome is 2.\n\n\n
Example 2:
\n\n\nInput: s = "letelt"\nOutput: 2\nExplanation:\nOne of the palindromes we can obtain from s in 2 moves is "lettel".\nOne of the ways we can obtain it is "letelt" -> "letetl" -> "lettel".\nOther palindromes such as "tleelt" can also be obtained in 2 moves.\nIt can be shown that it is not possible to obtain a palindrome in less than 2 moves.\n\n\n
\n
Constraints:
\n\n1 <= s.length <= 2000s consists only of lowercase English letters.s can be converted to a palindrome using a finite number of moves.给你一个只包含小写英文字母的字符串 s 。
每一次 操作 ，你可以选择 s 中两个 相邻 的字符，并将它们交换。
请你返回将 s 变成回文串的 最少操作次数 。
注意 ，输入数据会确保 s 一定能变成一个回文串。
\n\n
示例 1：
\n\n输入：s = \"aabb\"\n输出：2\n解释：\n我们可以将 s 变成 2 个回文串，\"abba\" 和 \"baab\" 。\n- 我们可以通过 2 次操作得到 \"abba\" ：\"aabb\" -> \"abab\" -> \"abba\" 。\n- 我们可以通过 2 次操作得到 \"baab\" ：\"aabb\" -> \"abab\" -> \"baab\" 。\n因此，得到回文串的最少总操作次数为 2 。\n\n\n
示例 2：
\n\n输入：s = \"letelt\"\n输出：2\n解释：\n通过 2 次操作从 s 能得到回文串 \"lettel\" 。\n其中一种方法是：\"letelt\" -> \"letetl\" -> \"lettel\" 。\n其他回文串比方说 \"tleelt\" 也可以通过 2 次操作得到。\n可以证明少于 2 次操作，无法得到回文串。\n\n\n
\n\n
提示：
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"isSubscribed": false,
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"editorType": "CKEDITOR",
"ugcQuestionId": null,
"style": "LEETCODE",
"exampleTestcases": "\"aabb\"\n\"letelt\"",
"__typename": "QuestionNode"
}
}
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