There are n couples sitting in 2n seats arranged in a row and want to hold hands.
The people and seats are represented by an integer array row where row[i] is the ID of the person sitting in the ith seat. The couples are numbered in order, the first couple being (0, 1), the second couple being (2, 3), and so on with the last couple being (2n - 2, 2n - 1).
Return the minimum number of swaps so that every couple is sitting side by side. A swap consists of choosing any two people, then they stand up and switch seats.
\n\n\n
Example 1:
\n\n\nInput: row = [0,2,1,3]\nOutput: 1\nExplanation: We only need to swap the second (row[1]) and third (row[2]) person.\n\n\n
Example 2:
\n\n\nInput: row = [3,2,0,1]\nOutput: 0\nExplanation: All couples are already seated side by side.\n\n\n
\n
Constraints:
\n\n2n == row.length2 <= n <= 30n is even.0 <= row[i] < 2nrow are unique.n 对情侣坐在连续排列的 2n 个座位上，想要牵到对方的手。
人和座位由一个整数数组 row 表示，其中 row[i] 是坐在第 i 个座位上的人的 ID。情侣们按顺序编号，第一对是 (0, 1)，第二对是 (2, 3)，以此类推，最后一对是 (2n-2, 2n-1)。
返回 最少交换座位的次数，以便每对情侣可以并肩坐在一起。 每次交换可选择任意两人，让他们站起来交换座位。
\n\n\n\n
示例 1:
\n\n\n输入: row = [0,2,1,3]\n输出: 1\n解释: 只需要交换row[1]和row[2]的位置即可。\n\n\n
示例 2:
\n\n\n输入: row = [3,2,0,1]\n输出: 0\n解释: 无需交换座位，所有的情侣都已经可以手牵手了。\n\n\n
\n\n
提示:
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