Seat Every Couple Together with Minimum Swaps

### Problem The 2n entries of row are distinct person IDs. Couples are (0,1), (2,3), and so forth. Seats are grouped as consecutive pairs (0,1), (2,3), etc. One swap exchanges any two people. Return the fewest swaps needed so each seat pair contains a couple. ```cpp class Solution { public: int minSwapsCouples(vector<int>& row); }; ``` ### Examples **Example 1:** ```text row = [0,3,2,1] Output: 1 Explanation: Swap IDs 3 and 1 to obtain [0,1,2,3]. ``` **Example 2:** ```text row = [1,0,3,2] Output: 0 Explanation: Every seat pair already contains partners. ``` ### Constraints - The array has exactly 2n entries with 2 <= n <= 30. - It is a permutation of the IDs from 0 through 2n-1. ### Contract considerations Count minimum swaps; the original callable returns an integer and does not request a sequence. ```hint Read the boundary condition How many swaps does one cycle of mixed couples require? ``` ### Boundary reminders Count minimum swaps; the original callable returns an integer and does not request a sequence.