13991399 SUSTech Online Judge
Problem 1399 --Edit The Sequence

## 1399: Edit The Sequence

Time Limit: 1 Sec  Memory Limit: 128 MB
Submit: 554  Solved: 121
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## Description

LowbieH implements a powerful editor for integer sequences.

The sequence is empty when the editor is initialized.

LowbieH creates 5 types of instructions for the editor:

$$I \ x$$  Insert x after the cursor.

$$D$$ Delete the element before the cursor

$$L$$ Move the cursor left. If the cursor has already been at the begin of the sequence, it will not move.

$$R$$ Move the cursor right. If the cursor has already been at the end of the sequence, it will not move.

$$Q \ k$$ Suppose that the current sequence $$BEFORE \ the \ cursor$$ is {$$a_1$$,$$a_2$$,...$$a_n$$}. Find $$max_{1 \le i\le k}S_i$$ where $$S_i = a_1 + a_2 + .. + a_i$$

## Input

And for each case: The first line contains an integer Q, which is the number of instructions. Then next Q lines contains contain an instruction as described above. (1 <= $$Q$$ <= $$10^6$$, $$|x| \le 1000$$ for $$I$$ instruction, $$1 \le k \le n$$ for $$Q$$ instruction)

## Output

For each $$Q$$ instruction, output the desired value.

## Sample Input

8
I 2
I -1
I 1
Q 3
L
D
R
Q 2

## Sample Output

2
3

## HINT

The sequence of sample test case after instructions is as follow(| denotes the cursor):

I 2  [2|]

I -1  [2 -1|]

I 1  [2 -1 1|]

Q 3  [2 -1 1|]

L    [2 -1| 1]

D    [2 | 1]

R    [2 1|]

Q 2 [2 1|]

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