[리트코드] 1204. Last Person to Fit in the Bus - 누적합 sum(컬럼) over (order by 컬럼), with 합치기 ✔️✔️✔️

 

# 문제

https://leetcode.com/problems/last-person-to-fit-in-the-bus/description/

 

# 문제 요약

 

총 무게합이 1000이하인 상태에서 마지막 탑승한 사람의 이름 구하기

 

 

# 헷갈렸던 부분

총 합계를 계산해야 해서 @set을 사용해야 하는줄 알았다

 

# 핵심 개념

 

누적합을 계산할때, 윈도우 함수를 이용할 수 있다

 

sum(컬럼) over (order by 컬럼) 을 사용하였다

 

sum(weight) over (order by turn)

 

 

# 코드 확인

with cte as (
    select *,
           sum(weight) over (order by turn) as num,
           case when sum(weight) over (order by turn) <= 1000 then 'yes'
                else 'no' end as 'yes_no'
    from Queue
    order by turn
)
select *
from cte

 

 

 

 

# 정답 코드

with cte as (
    select *,
           sum(weight) over (order by turn) as num,
           case when sum(weight) over (order by turn) <= 1000 then 'yes'
                else 'no' end as 'yes_no'
    from Queue
    order by turn
)
select person_name
from cte
where num = (select max(num)
             from cte
             where yes_no = 'yes')