题目描述
Problem Description
Translated from JOI Open 2017 T2 "Bulldozer"
There are $N$ points on a plane, where point $i$ (for $1 \leq i \leq N$) is located at $(X_i, Y_i)$. Each point $i$ has a weight $W_i$, which is a non-zero integer (it can be negative).
The total value obtained by drawing two parallel lines on the plane is the sum of the weights of all points between the lines (including those on the lines). Determine the maximum total value that can be achieved.
Input Format
The first line contains an integer $N$.
The next $N$ lines each contain three space-separated integers $X_i, Y_i, W_i$.
Output Format
Output a single integer, which is the maximum total value.
Sample Input and Output
Sample Input #1
5
-5 5 -2
2 5 10
1 4 -2
4 -5 4
-2 2 7
Sample Output #1
19
Sample Input #2
6
0 0 6
1 0 -2
2 0 8
0 1 -2
1 1 5
2 1 -2
Sample Output #2
15
Sample Input #3
5
0 0 2
4 0 2
3 2 -1
1 2 2
1 1 -1
Sample Output #3
5
Sample Input #4
2
0 0 -1
1 0 -1
Sample Output #4
0
Notes
Sample Explanation 1

Choose points $2, 3, 4, 5$.
Sample Explanation 2
Note that points $1, 2, 3$ are collinear. Points $4, 5, 6$ are also collinear.
Sample Explanation 3
In this sample, no three points are collinear. The chosen parallel lines pass through points $1, 2$ and points $3, 4$.
Data Range
All input data satisfies the following conditions:
$1 \leq N \leq 2000$, $|X_i|, |Y_i| \leq 10^9$, $1 \leq |W_i| \leq 10^9$ (for $1 \leq i \leq N$). $(X_i, Y_i) \neq (X_j, Y_j)$ (for $1 \leq i < j \leq N$).
| Subtask | Score | $N \leq 100$ | No three points are collinear | Lines through different points are not parallel | Additional Conditions |
|---|---|---|---|---|---|
| 1 | 5 | √ | × | × | All points are on the x-axis |
| 2 | 20 | √ | √ | √ | None |
| 3 | 35 | × | √ | √ | None |
| 4 | 20 | × | √ | × | None |
| 5 | 20 | × | × | × | None |
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分