You are given a 0-indexed permutation of n integers nums.
A permutation is called semi-ordered if the first number equals 1 and the last number equals n. You can perform the below operation as many times as you want until you make nums a semi-ordered permutation:
nums, then swap them.Return the minimum number of operations to make nums a semi-ordered permutation.
A permutation is a sequence of integers from 1 to n of length n containing each number exactly once.
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Example 1:
\n\n\nInput: nums = [2,1,4,3]\nOutput: 2\nExplanation: We can make the permutation semi-ordered using these sequence of operations: \n1 - swap i = 0 and j = 1. The permutation becomes [1,2,4,3].\n2 - swap i = 2 and j = 3. The permutation becomes [1,2,3,4].\nIt can be proved that there is no sequence of less than two operations that make nums a semi-ordered permutation. \n\n\n
Example 2:
\n\n\nInput: nums = [2,4,1,3]\nOutput: 3\nExplanation: We can make the permutation semi-ordered using these sequence of operations:\n1 - swap i = 1 and j = 2. The permutation becomes [2,1,4,3].\n2 - swap i = 0 and j = 1. The permutation becomes [1,2,4,3].\n3 - swap i = 2 and j = 3. The permutation becomes [1,2,3,4].\nIt can be proved that there is no sequence of less than three operations that make nums a semi-ordered permutation.\n\n\n
Example 3:
\n\n\nInput: nums = [1,3,4,2,5]\nOutput: 0\nExplanation: The permutation is already a semi-ordered permutation.\n\n\n
\n
Constraints:
\n\n2 <= nums.length == n <= 501 <= nums[i] <= 50nums is a permutation.给你一个下标从 0 开始、长度为 n 的整数排列 nums 。
如果排列的第一个数字等于 1 且最后一个数字等于 n ，则称其为 半有序排列 。你可以执行多次下述操作，直到将 nums 变成一个 半有序排列 ：
nums 中相邻的两个元素，然后交换它们。返回使 nums 变成 半有序排列 所需的最小操作次数。
排列 是一个长度为 n 的整数序列，其中包含从 1 到 n 的每个数字恰好一次。
\n\n
示例 1：
\n\n\n输入：nums = [2,1,4,3]\n输出：2\n解释：可以依次执行下述操作得到半有序排列：\n1 - 交换下标 0 和下标 1 对应元素。排列变为 [1,2,4,3] 。\n2 - 交换下标 2 和下标 3 对应元素。排列变为 [1,2,3,4] 。\n可以证明，要让 nums 成为半有序排列，不存在执行操作少于 2 次的方案。\n\n
示例 2：
\n\n\n输入：nums = [2,4,1,3]\n输出：3\n解释：\n可以依次执行下述操作得到半有序排列：\n1 - 交换下标 1 和下标 2 对应元素。排列变为 [2,1,4,3] 。\n2 - 交换下标 0 和下标 1 对应元素。排列变为 [1,2,4,3] 。\n3 - 交换下标 2 和下标 3 对应元素。排列变为 [1,2,3,4] 。\n可以证明，要让 nums 成为半有序排列，不存在执行操作少于 3 次的方案。\n\n\n
示例 3：
\n\n\n输入：nums = [1,3,4,2,5]\n输出：0\n解释：这个排列已经是一个半有序排列，无需执行任何操作。\n\n\n
\n\n
提示：
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