[백준] 라면 사기 (Small)

https://sangsangss.tistory.com/187

n=int(input())
lst = list(map(int, input().split()))
lst.append(0)
lst.append(0)
ans =0
for i in range(len(lst)):
    count = lst[i]
    if count==0:
        continue
    if lst[i+1]==0:
        ans+=count*3
        continue
    else:
        if lst[i+2]==0:
            lst[i+1]-=count
            if lst[i+1]<0:
                lst[i+1]=0
            ans+=count*5
        else:
            lst[i+1]-=count
            lst[i+2]-=count
            if lst[i+1]<0:
                lst[i+1]=0
            if lst[i+2]<0:
                lst[i+2]=0
            ans+=count*7
print(ans)

It was only right for some test cases because my thought process was like this. I wanted to make the lst[i] to 0 always. But this is wrong.

We do need to sometimes use 2 factories instead of 3 like here