题目描述
Problem Statement
We have K sequences.
The i-th sequence A_i has the length of N_i.
Takahashi and Aoki will play a game using these.
They will alternately do the following operation until the length of every sequence becomes 1:
- Choose a sequence of length at least 2, and delete its first or last element.
Takahashi goes first. Takahashi wants to maximize the sum of the K elements remaining in the end, while Aoki wants to minimize it.
Find the sum of the K elements remaining in the end when both players play optimally.
Input
Input is given from Standard Input in the following format:
K
$N_1 A_{1, 1} A_{1, 2} \cdots A_{1, N_1}$
$N_2 A_{2, 1} A_{2, 2} \cdots A_{2, N_2}$
$\vdots$
$N_K A_{K, 1} A_{K, 2} \cdots A_{K, N_K}$
Output
Print the answer.
Constraints
- All values in input are integers.
- $1 \leq K \leq 2 \times 10^5$
- $1 \leq N_i$
- $\sum_i N_i \leq 2 \times 10^5$
- $1 \leq A_{i, j} \leq 10^9$
Sample Input 1
2
3 1 2 3
2 1 10
Sample Output 1
12
Here is one possible progression of the game:
- Takahashi deletes the first element of A_2. Now we have $A_1 = \left(1, 2, 3\right), A_2 = \left(10\right)$.
- Aoki deletes the last element of A_1. Now we have $A_1 = \left(1, 2\right), A_2 = \left(10\right)$.
- Takahashi deletes the first element of A_1. Now we have $A_1 = \left(2\right), A_2 = \left(10\right)$. The length of every sequence has become 1, so the game ends.
In this case, the sum of the K elements remaining in the end is 12. Note that the players may have made suboptimal moves here.
Sample Input 2
8
1 2
2 1 2
3 1 2 1
4 1 1 1 2
5 1 1 2 2 1
6 2 2 2 2 1 1
7 1 2 1 1 2 2 2
8 2 2 2 1 1 1 1 2
Sample Output 2
12
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分