603. 连续空余座位

English Version

题目描述

表: Cinema

+-------------+------+
| Column Name | Type |
+-------------+------+
| seat_id     | int  |
| free        | bool |
+-------------+------+
在 SQL 中，Seat_id 是该表的自动递增主键列。
该表的每一行表示第 i 个座位是否空闲。1 表示空闲，0 表示被占用。

 

查找电影院所有连续可用的座位。

返回按 seat_id 升序排序 的结果表。

测试用例的生成使得两个以上的座位连续可用。

结果表格式如下所示。

 

示例 1:

输入: 
Cinema 表:
+---------+------+
| seat_id | free |
+---------+------+
| 1       | 1    |
| 2       | 0    |
| 3       | 1    |
| 4       | 1    |
| 5       | 1    |
+---------+------+
输出: 
+---------+
| seat_id |
+---------+
| 3       |
| 4       |
| 5       |
+---------+

解法

SQL

# Write your MySQL query statement below
SELECT DISTINCT a.seat_id
FROM
    Cinema AS a
    JOIN Cinema AS b ON abs(a.seat_id - b.seat_id) = 1 AND a.free AND b.free
ORDER BY 1;

# Write your MySQL query statement below
WITH
    T AS (
        SELECT
            seat_id,
            (free + (lag(free) OVER (ORDER BY seat_id))) AS a,
            (free + (lead(free) OVER (ORDER BY seat_id))) AS b
        FROM Cinema
    )
SELECT seat_id
FROM T
WHERE a = 2 OR b = 2;