1386. Cinema Seat Allocation

A cinema has `n` rows of seats, numbered from 1 to `n` and there are ten seats in each row, labelled from 1 to 10 as shown in the figure above.

Given the array `reservedSeats` containing the numbers of seats already reserved, for example, `reservedSeats[i]=[3,8]` means the seat located in row 3 and labelled with 8 is already reserved.

Return the maximum number of four-person families you can allocate on the cinema seats. A four-person family occupies fours seats in one row, that are next to each other. Seats across an aisle (such as [3,3] and [3,4]) are not considered to be next to each other, however, It is permissible for the four-person family to be separated by an aisle, but in that case, exactly two people have to sit on each side of the aisle.

Example 1:

```Input: n = 3, reservedSeats = [[1,2],[1,3],[1,8],[2,6],[3,1],[3,10]]
Output: 4
Explanation: The figure above shows the optimal allocation for four families, where seats mark with blue are already reserved and contiguous seats mark with orange are for one family.
```

Example 2:

```Input: n = 2, reservedSeats = [[2,1],[1,8],[2,6]]
Output: 2
```

Example 3:

```Input: n = 4, reservedSeats = [[4,3],[1,4],[4,6],[1,7]]
Output: 4
```

Constraints:

• `1 <= n <= 10^9`
• `1 <= reservedSeats.length <= min(10*n, 10^4)`
• `reservedSeats[i].length == 2`
• `1 <= reservedSeats[i][0] <= n`
• `1 <= reservedSeats[i][1] <= 10`
• All `reservedSeats[i]` are distinct.

Medium

Normal

Microsoft

Solution(Chinese):

LEETCODE 1386. Cinema Seat Allocation 解题思路分析