#bzoj4989. Why Did the Cow Cross the Road

Why Did the Cow Cross the Road

Title Description

Why did the cow cross the road? We may never know the full reason, but it is certain that Farmer John's cows do end up crossing the road quite frequently. In fact, they end up crossing the road so often that they often bump into each-other when their paths cross, a situation Farmer John would like to remedy.Farmer John raises NN breeds of cows , and each of his fields is dedicated to grazing for one specific breed; for example, a field dedicated to breed 1212 can only be used for cows of breed 1212 and not of any other breed. A long road runs through his farm. There is a sequence of NNNN fields on one side of the road (one for each breed), and a sequence of NN fields on the other side of the road (also one for each breed). When a cow crosses the road, she therefore crosses between the two fields designated for her specific breed.

Had Farmer John planned more carefully, he would have ordered the fields by breed the same way on both sides of the road, so the two fields for each breed would be directly across the road from each-other. This would have allowed cows to cross the road without any cows from different breeds bumping into one-another. Alas, the orderings on both sides of the road might be different, so Farmer John observes that there might be pairs of breeds that cross. A pair of different breeds (a,b)(a,b) is "crossing" if any path across the road for breed aa must int ersect any path across the road for breed bbbb.

Farmer John would like to minimize the number of crossing pairs of breeds. For logistical reasons, he figures he can move cows around on one side of the road so the fields on that side undergo a "cyclic shift". That is, for some 0k<N0≤k<N, every cow re-locates to the field kk fields ahead of it, with the cows in the last kk fields moving so they now populate the first kk fields. For example, if the fields on one side of the road start out ordered by breed as 3,7,1,2,5,4,63, 7, 1, 2, 5, 4, 6 and undergo a cyclic shift by k=2k=2, the new order will be 4,6,3,7,1,2,54, 6, 3, 7, 1, 2, 5. Please determine the minimum possible number of crossing pairs of breeds that can exist after an appropriate cyclic shift of the fields on one side of the road.

There are two sequences AA and BB corresponding to the upper and lower positions, with a length of n, and the two sequences are arranged in an arrangement of n. When Ai=BjA_i=B_j, there will be an edge connecting the top and bottom. You can choose sequence AA or sequence BB to rotate any KK steps Rotate two steps, such as 3,4,1,5,23,4,1,5,2 to obtain 5,2,3,4,15,2,3,4,1.

Find the logarithm of the minimum intersecting line segment after rotation.

Input format

The first line of input contains N.

The next N lines describe the order, by breed ID, of fields on one side of the road;

The last N lines describe the order, by breed ID, of the fields on the other side of the road.

Output format

Please output the minimum number of crossing pairs of varieties after cyclic shifting of fields on one side of the road (any side can be shifted).

Example

5 5 4 1 3 2 1 3 2 5 4
0

Data scale and agreement

For 100%100\% of the data: 1N105,1IDn1 ≤ N ≤ 10^5, 1≤ID≤n.