7582: [CSES Problem Set] Planets Queries II
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Description
You are playing a game consisting of $n$ planets. Each planet has a teleporter to another planet (or the planet itself).
You have to process $q$ queries of the form: You are now on planet $a$ and want to reach planet $b$. What is the minimum number of teleportations?
You have to process $q$ queries of the form: You are now on planet $a$ and want to reach planet $b$. What is the minimum number of teleportations?
Input
The first input line contains two integers $n$ and $q$: the number of planets and queries. The planets are numbered $1,2,\ldots,n$.
The second line contains $n$ integers $t_1,t_2,\ldots,t_n$: for each planet, the destination of the teleporter.
Finally, there are $q$ lines describing the queries. Each line has two integers $a$ and $b$: you are now on planet $a$ and want to reach planet $b$.
The second line contains $n$ integers $t_1,t_2,\ldots,t_n$: for each planet, the destination of the teleporter.
Finally, there are $q$ lines describing the queries. Each line has two integers $a$ and $b$: you are now on planet $a$ and want to reach planet $b$.
Output
For each query, print the minimum number of teleportations. If it is not possible to reach the destination, print $-1$.
Constraints
$1≤n,q≤2⋅10^5$
$1 \le a,b \le n$
$1 \le a,b \le n$
Sample 1 Input
5 3
2 3 2 3 2
1 2
1 3
1 4
Sample 1 Output
1
2
-1