We have two sequences A and B consisting of integers, both of length N, and you would like them to be (strictly) increasing, i.e. for each K (0 ≤ K < N − 1), A[K] < A[K + 1] and B[K] < B[K + 1]. Thus, you need to modify the sequences, but the only manipulation you can perform is to swap an arbitrary element in sequence A with the corresponding element in sequence B. That is, both elements to be exchanged must occupy the same index position within each sequence.
For example, given A = [5, 3, 7, 7, 10] and B = [1, 6, 6, 9, 9], you can swap elements at positions 1 and 3, obtaining A = [5, 6, 7, 9, 10], B = [1, 3, 6, 7, 9].
Your goal is make both sequences increasing, using the smallest number of swaps.
Write a function:
public int minswaps(int[] A, int[] B);
that, given two zero-indexed arrays A, B of length N, containing integers, returns the minimum number of swapping operations required to make the given arrays increasing. If it is impossible to achieve the goal, return −1.
For example, given:
A[0] = 5 B[0] = 1
A[1] = 3 B[1] = 6
A[2] = 7 B[2] = 6
A[3] = 7 B[3] = 9
A[4] = 10 B[4] = 9
your function should return 2, as explained above.
Given:
A[0] = 5 B[0] = 2
A[1] = -3 B[1] = 6
A[2] = 6 B[2] = -5
A[3] = 4 B[3] = 1
A[4] = 8 B[4] = 0
your function should return −1, since you cannot perform operations that would make the sequences become increasing.
Given:
A[0] = 1 B[0] = -2
A[1] = 5 B[1] = 0
A[2] = 6 B[2] = 2
your function should return 0, since the sequences are already increasing.
Assume that:
N is an integer within the range [2..100,000];
each element of arrays A, B is an integer within the range [−1,000,000,000..1,000,000,000];
A and B have equal lengths.
Complexity O(N)
