题目描述
Problem Background
Xiao C loves data structures involving interval operations because such problems always have an easy $\mathcal{O}\left(n^2\right)$ partial score.
Problem Description
This problem has a large input size, it is recommended to use fast input methods, refer to Contest Announcement Board
Xiao C has a sequence $a$ of length $n$, where the $i$-th element is $a_i$.
$a$ is a permutation of $1$ to $n$ (i.e., each number from $1$ to $n$ appears exactly once in $a$).
Define $\operatorname{Mex}_{l,r}$ as the smallest positive integer not present in $\{a_l, a_{l+1}, \cdots, a_{r-1}, a_r\}$.
For example, $\operatorname{Mex}\{2,3\}=1, \operatorname{Mex}\{1,2,3\}=4$.
Xiao C also has a sequence $f$ of length $n$.
An interval $\left[l,r\right]$ is considered valid if and only if
$$f_{r-l+1} < \operatorname{Mex}_{l,r}$$
Xiao C wants you to tell him the length of the shortest valid interval. Specifically, if no valid interval exists, output 0.
Input Format
The first line contains a positive integer $n$.
The second line contains $n$ positive integers $a_1, a_2, \cdots, a_n$.
The third line contains $n$ positive integers $f_1, f_2, \cdots, f_n$.
Output Format
A single integer representing the length of the shortest valid interval.
Sample Input and Output
Sample Input #1
5
2 3 1 5 4
2 2 3 4 5
Sample Output #1
3
Sample Input #2
5
2 3 1 5 4
1 2 2 4 5
Sample Output #2
1
Sample Input #3
5
1 3 4 2 5
6 7 8 9 10
Sample Output #3
0
Sample Input #4
See attachment
Sample Output #4
See attachment
Notes/Hints
Sample Explanation
For #1, it is easy to find that $\left[1,3\right]$ is the shortest valid interval.
For #2, it is easy to find that $\left[3,3\right]$ is the shortest valid interval.
For #3, it is easy to find that there is no valid interval.
For $10\%$ of the data, $1 \leq n \leq 100$.
For $20\%$ of the data, $1 \leq n \leq 1000$.
For another $10\%$ of the data, $f$ is non-increasing, i.e., $f_1 \geq f_2 \geq \cdots \geq f_n$, and $1 \leq n \leq 10^6$.
For $100\%$ of the data, $1 \leq n \leq 4 \times 10^6, 1 \leq f_i \leq 10^9$.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分