# For Solution

There are `n` rooms you need to visit, labeled from `0` to `n - 1`. Each day is labeled, starting from `0`. You will go in and visit one room a day.

Initially on day `0`, you visit room `0`. The order you visit the rooms for the coming days is determined by the following rules and a given 0-indexed array `nextVisit` of length `n`:

• Assuming that on a day, you visit room `i`,
• if you have been in room `i` an odd number of times (including the current visit), on the next day you will visit the room specified by `nextVisit[i]` where `0 <= nextVisit[i] <= i`;
• if you have been in room `i` an even number of times (including the current visit), on the next day you will visit room `(i + 1) mod n`.

Return the label of the first day where you have been in all the rooms. It can be shown that such a day exists. Since the answer may be very large, return it modulo `109 + 7`. Example 1:

```Input: nextVisit = [0,0]
Output: 2
Explanation:
- On day 0, you visit room 0. The total times you have been in room 0 is 1, which is odd.
On the next day you will visit room nextVisit = 0
- On day 1, you visit room 0, The total times you have been in room 0 is 2, which is even.
On the next day you will visit room (0 + 1) mod 2 = 1
- On day 2, you visit room 1. This is the first day where you have been in all the rooms.
```

Example 2:

```Input: nextVisit = [0,0,2]
Output: 6
Explanation:
Your room visiting order for each day is: [0,0,1,0,0,1,2,...].
Day 6 is the first day where you have been in all the rooms.
```

Example 3:

```Input: nextVisit = [0,1,2,0]
Output: 6
Explanation:
Your room visiting order for each day is: [0,0,1,1,2,2,3,...].
Day 6 is the first day where you have been in all the rooms.
```

Constraints:

• `n == nextVisit.length`
• `2 <= n <= 105`
• `0 <= nextVisit[i] <= i`