problem0855

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855. Exam Room

题目

In an exam room, there are N seats in a single row, numbered 0, 1, 2, ..., N-1.

When a student enters the room, they must sit in the seat that maximizes the distance to the closest person. If there are multiple such seats, they sit in the seat with the lowest number. (Also, if no one is in the room, then the student sits at seat number 0.)

Return a class ExamRoom(int N)that exposes two functions: ExamRoom.seat()returning an intrepresenting what seat the student sat in, and ExamRoom.leave(int p)representing that the student in seat number pnow leaves the room. It is guaranteed that any calls to ExamRoom.leave(p) have a student sitting in seat p.

Example 1:

Input: ["ExamRoom","seat","seat","seat","seat","leave","seat"], [[10],[],[],[],[],[4],[]]
Output: [null,0,9,4,2,null,5]
Explanation:
ExamRoom(10) -> null
seat() -> 0, no one is in the room, then the student sits at seat number 0.
seat() -> 9, the student sits at the last seat number 9.
seat() -> 4, the student sits at the last seat number 4.
seat() -> 2, the student sits at the last seat number 2.
leave(4) -> null
seat() -> 5, the student​​​​​​​ sits at the last seat number 5.

Note:

1. 1 <= N <= 10^9
2. ExamRoom.seat() and ExamRoom.leave() will be called at most 10^4 times across all test cases.
3. Calls to ExamRoom.leave(p) are guaranteed to have a student currently sitting in seat number p.

解题思路

见程序注释

Documentation

Index

• type ExamRoom
  • func Constructor(N int) ExamRoom
  • func (r *ExamRoom) Leave(p int)
  • func (r *ExamRoom) Seat() int

Types

type ExamRoom

type ExamRoom struct {
	N int
	// contains filtered or unexported fields
}

ExamRoom 是题目需要的结构体

func Constructor

func Constructor(N int) ExamRoom

Constructor 创建 ExamRoom

func (*ExamRoom) Leave

func (r *ExamRoom) Leave(p int)

Leave 表示有人离座

func (*ExamRoom) Seat

func (r *ExamRoom) Seat() int

Seat 表示有人入座