README_EN.md

603. Consecutive Available Seats

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Description

Table: Cinema

+-------------+------+
| Column Name | Type |
+-------------+------+
| seat_id     | int  |
| free        | bool |
+-------------+------+
seat_id is an auto-increment primary key column for this table.
Each row of this table indicates whether the ith seat is free or not. 1 means free while 0 means occupied.

 

Write an SQL query to report all the consecutive available seats in the cinema.

Return the result table ordered by seat_id in ascending order.

The test cases are generated so that more than two seats are consecutively available.

The query result format is in the following example.

 

Example 1:

Input: 
Cinema table:
+---------+------+
| seat_id | free |
+---------+------+
| 1       | 1    |
| 2       | 0    |
| 3       | 1    |
| 4       | 1    |
| 5       | 1    |
+---------+------+
Output: 
+---------+
| seat_id |
+---------+
| 3       |
| 4       |
| 5       |
+---------+

Solutions

SQL

SELECT c1.seat_id
FROM   Cinema c1,
       Cinema c2
WHERE  ( ( c1.seat_id = c2.seat_id + 1 )
          OR ( c1.seat_id = c2.seat_id - 1 ) )
       AND ( c1.free = 1
             AND c2.free = 1 )
GROUP BY seat_id;