Types: n: int, k: int, a: List[int]
Ranges: 2 ≤ n ≤ 8000, 0 ≤ k ≤ min(n/2, 20), 1 ≤ a[i] ≤ n
Addtl Info: n is even, a[i] ≠ i, a_i ≠ a_j for i ≠ j, a[a_i] = i