codeforces#P1359D. Yet Another Yet Another Task
Yet Another Yet Another Task
Description
Alice and Bob are playing yet another card game. This time the rules are the following. There are $n$ cards lying in a row in front of them. The $i$-th card has value $a_i$.
First, Alice chooses a non-empty consecutive segment of cards $[l; r]$ ($l \le r$). After that Bob removes a single card $j$ from that segment $(l \le j \le r)$. The score of the game is the total value of the remaining cards on the segment $(a_l + a_{l + 1} + \dots + a_{j - 1} + a_{j + 1} + \dots + a_{r - 1} + a_r)$. In particular, if Alice chooses a segment with just one element, then the score after Bob removes the only card is $0$.
Alice wants to make the score as big as possible. Bob takes such a card that the score is as small as possible.
What segment should Alice choose so that the score is maximum possible? Output the maximum score.
The first line contains a single integer $n$ ($1 \le n \le 10^5$) — the number of cards.
The second line contains $n$ integers $a_1, a_2, \dots, a_n$ ($-30 \le a_i \le 30$) — the values on the cards.
Print a single integer — the final score of the game.
Input
The first line contains a single integer $n$ ($1 \le n \le 10^5$) — the number of cards.
The second line contains $n$ integers $a_1, a_2, \dots, a_n$ ($-30 \le a_i \le 30$) — the values on the cards.
Output
Print a single integer — the final score of the game.
Samples
5
5 -2 10 -1 4
6
8
5 2 5 3 -30 -30 6 9
10
3
-10 6 -15
0
Note
In the first example Alice chooses a segment $[1;5]$ — the entire row of cards. Bob removes card $3$ with the value $10$ from the segment. Thus, the final score is $5 + (-2) + (-1) + 4 = 6$.
In the second example Alice chooses a segment $[1;4]$, so that Bob removes either card $1$ or $3$ with the value $5$, making the answer $5 + 2 + 3 = 10$.
In the third example Alice can choose any of the segments of length $1$: $[1;1]$, $[2;2]$ or $[3;3]$. Bob removes the only card, so the score is $0$. If Alice chooses some other segment then the answer will be less than $0$.