Preparing NOJ

# Nauuo and Cards

1000ms 262144K

## Description:

Nauuo is a girl who loves playing cards.

One day she was playing cards but found that the cards were mixed with some empty ones.

There are $n$ cards numbered from $1$ to $n$, and they were mixed with another $n$ empty cards. She piled up the $2n$ cards and drew $n$ of them. The $n$ cards in Nauuo's hands are given. The remaining $n$ cards in the pile are also given in the order from top to bottom.

In one operation she can choose a card in her hands and play it — put it at the bottom of the pile, then draw the top card from the pile.

Nauuo wants to make the $n$ numbered cards piled up in increasing order (the $i$-th card in the pile from top to bottom is the card $i$) as quickly as possible. Can you tell her the minimum number of operations?

## Input:

The first line contains a single integer $n$ ($1\le n\le 2\cdot 10^5$) — the number of numbered cards.

The second line contains $n$ integers $a_1,a_2,\ldots,a_n$ ($0\le a_i\le n$) — the initial cards in Nauuo's hands. $0$ represents an empty card.

The third line contains $n$ integers $b_1,b_2,\ldots,b_n$ ($0\le b_i\le n$) — the initial cards in the pile, given in order from top to bottom. $0$ represents an empty card.

It is guaranteed that each number from $1$ to $n$ appears exactly once, either in $a_{1..n}$ or $b_{1..n}$.

## Output:

The output contains a single integer — the minimum number of operations to make the $n$ numbered cards piled up in increasing order.

## Sample Input:

 3 0 2 0 3 0 1

## Sample Output:

 2

## Sample Input:

 3 0 2 0 1 0 3

## Sample Output:

 4

## Sample Input:

 11 0 0 0 5 0 0 0 4 0 0 11 9 2 6 0 8 1 7 0 3 0 10

## Sample Output:

 18

## Note:

Example 1

We can play the card $2$ and draw the card $3$ in the first operation. After that, we have $[0,3,0]$ in hands and the cards in the pile are $[0,1,2]$ from top to bottom.

Then, we play the card $3$ in the second operation. The cards in the pile are $[1,2,3]$, in which the cards are piled up in increasing order.

Example 2

Play an empty card and draw the card $1$, then play $1$, $2$, $3$ in order.

Info

Provider CodeForces

Code CF1172A

Tags

greedyimplementation

Submitted 102

Passed 31

AC Rate 30.39%

Date 07/21/2019 13:40:31

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