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# 765. Couples Holding Hands

## Description

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 `i`

seat. The couples are numbered in order, the first couple being ^{th}`(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.

**Example 1:**

Input:row = [0,2,1,3]Output:1Explanation:We only need to swap the second (row[1]) and third (row[2]) person.

**Example 2:**

Input:row = [3,2,0,1]Output:0Explanation:All couples are already seated side by side.

**Constraints:**

`2n == row.length`

`2 <= n <= 30`

`n`

is even.`0 <= row[i] < 2n`

- All the elements of
`row`

are**unique**.