A cinema has
n rows of seats, numbered from 1 to
n and there are ten seats in each row, labeled 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 labeled with 8 is already reserved.
Return the maximum number of four-person groups you can assign to the cinema seats. A four-person group occupies four adjacent seats in one single row. Seats across an aisle (such as [3,3] and [3,4]) are not considered to be adjacent, but there is an exceptional case on which an aisle split a four-person group, in that case, the aisle split a four-person group in the middle, which means to have two people on each side.
Input: n = 3, reservedSeats = [[1,2],[1,3],[1,8],[2,6],[3,1],[3,10]]
Explanation: The figure above shows the optimal allocation for four groups, where seats mark with blue are already reserved and contiguous seats mark with orange are for one group.
Input: n = 2, reservedSeats = [[2,1],[1,8],[2,6]]
Input: n = 4, reservedSeats = [[4,3],[1,4],[4,6],[1,7]]
1 <= n <= 10^9
1 <= reservedSeats.length <= min(10*n, 10^4)
reservedSeats[i].length == 2
1 <= reservedSeats[i] <= n
1 <= reservedSeats[i] <= 10
- Time complexity: O(n). The complete array of size n is traversed.
- Space complexity: O(n). An additional dictionary is used to map the row to seat information.