COCI '16 Contest 1 #5 Kralj

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Points: 15 (partial)
Time limit: 1.0s
Memory limit: 128M

Problem types

Young ruler Mirko has declared himself king of dwarves. Upon hearing this, Slavko felt threatened and soon declared himself king of elves! As there cannot be more than one king in the land, they have decided to resolve the issue of power once and for all.

Slavko will, along with N strongest elves of the kingdom, labeled with numbers from 1 to N, go visit Mirko's castle. In the castle hall, they will be greeted by N strongest dwarves sitting in a circle, labeled clockwise with numbers from 1 to N.

Mirko has, upon entering the castle, given a number A_i to each of Slavko's elves – the label of the dwarf it will fight against. Unfortunately, he didn't make sure that each elf should get a unique adversary, and soon a terrible fight broke out.

They have decided to solve the problem in the following way:

  • Slavko will send his elves to the hall one by one, in the order he chooses. The next elf can enter the hall only after the one before him found a place to sit.
  • The elf labeled k will first approach the dwarf labeled A_k. If there isn't an elf sitting beside the dwarf, he will sit there. Otherwise, he will continue walking, from dwarf to dwarf, clockwise, until he finds an unclaimed dwarf.

Now the N resulting pairs of elves and dwarves compete in arm wrestling, and the stronger one always wins.

Slavko is well prepared for this event. He has studied all the fighters and determined the strength of each one. Now he wants to send the elves to the hall in the order which, after they all sit down, will bring the most victories for him.

Help him and calculate the highest number of victories in duels that can be achieved by elves!

Input Specification

The first line of input contains the integer N (1 \le N \le 5 \cdot 10^5).
The second line of input contains N integers A_i (1 \le A_i \le N), the adversaries chosen by Mirko.
The third line of input contains N integers P_i (1 \le P_i \le 10^9), the dwarves' strengths.
The fourth line of input contains N integers V_i (1 \le V_i \le 10^9), the elves' strengths.
All strengths from the input will be mutually distinct.

Output Specification

The first and only line of output must contain the maximum number of victories that can be achieved by elves.

Scoring

In test cases worth 40\% of total points, Mirko will choose the dwarf labeled with 1 (A_i = 1 for each i from 1 to N) as an adversary in each elf duel.

Sample Input 1

3
2 3 3
4 1 10
2 7 3

Sample Output 1

2

Explanation for Sample Output 1

Slavko can sort the elves in the following way: 3, 2, 1. This way, the elf number 3 will sit beside dwarf number 3, elf 2 will have to move one seat clockwise and sit beside dwarf 1, and the elf number 2 will sit beside the dwarf number 2. Elves 1 and 2 will win their duels, and elf 3 will lose.

Sample Input 2

4
3 1 3 3
5 8 7 10
4 1 2 6

Sample Output 2

1

Sample Input 3

3
1 2 3
8 4 3
9 2 6

Sample Output 3

2

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