第 76 场 AtCoder Grand Contest
E
Squared Norm Maximization
AtCoder
未评级
原题
← D→

Squared Norm MaximizationAI (CI翻译)

Problem Statement

You are given $N$ pairs of integers $(A_1,B_1),(A_2,B_2),\cdots,(A_N,B_N)$.

For a subset $s$ of $\{1,2,\cdots,N\}$, we define its score as follows:

  • $(\sum_{i \in s} A_i)^2 + (\sum_{i \in s} B_i)^2 - 3 \sum_{i \in s} (A_i^2+B_i^2)$

Find the maximum possible value of the score.

Solve $T$ cases for one input.

Constraints

  • $1 \leq T \leq 250000$
  • $1 \leq N \leq 250000$
  • $\sum_{1 \leq i \leq N} |A_i| \leq 10^9$
  • $\sum_{1 \leq i \leq N} |B_i| \leq 10^9$
  • The sum of $N$ over the $T$ cases is at most $250000$.
  • All input values are integers.

Input

The input is given from Standard Input in the following format:

T
case_1
case_2
\vdots
case_T

Each test case is given in the following format:

N
A_1 B_1
A_2 B_2
\vdots
A_N B_N

Output

Output $T$ lines. The $i$-th line should contain the answer for the $i$-th case.

{"titleZh":"平方范数最大化","bodyZh":"## 题目描述\n\n给定 $N$ 对整数 $(A_1,B_1),(A_2,B_2),\\cdots,(A_N,B_N)$。\n\n对于集合 $\{1,2,\\cdots,N\\}$ 的一个子集 $s$,其得分定义如下:\n\n- $(\\sum_{i \\in s} A_i)^2 + (\\sum_{i \\in s} B_i)^2 - 3 \\sum_{i \\in s} (A_i^2+B_i^2)$\n\n求得分可能达到的最大值。\n\n对于一个输入,需要解决 $T$ 个测试用例。\n\n## 约束条件\n\n- $1 \\leq T \\leq 250000$\n- $1 \\leq N \\leq 250000$\n- $\\sum_{1 \\leq i \\leq N} |A_i| \\leq 10^9$\n- $\\sum_{1 \\leq i \\leq N} |B_i| \\leq 10^9$\n- 所有测试用例的 $N$ 之和不超过 $250000$。\n- 所有输入值均为整数。\n\n## 输入格式\n\n输入从标准输入按以下格式给出:\n\n\nT\ncase_1\ncase_2\n\\vdots\ncase_T\n`\n\n每个测试用例按以下格式给出:\n\n`\nN\nA_1 B_1\nA_2 B_2\n\\vdots\nA_N B_N\n\n\n## 输出格式\n\n输出 $T$ 行。第 $i$ 行应包含第 $i$ 个测试用例的答案。"}AI (CI翻译)

样例

Input #1
4
4
1 0
0 1
-1 0
0 -1
4
1 0
1 0
1 0
1 0
6
1 -9
-7 -2
0 -10
10 1
2 -8
1 -8
10
19271058 -140039457
-3441379 -134156148
227767903 -70474702
-837477 -74699717
153584327 80404336
115741008 -22141349
-190028077 -21940357
76149725 17176032
159846847 -296045185
-53332199 142922717
Output #1
0
4
296
178262497119089558
In the first case, if $s=\{\}$, the score is $0$, which is the maximum. In the second case, if $s=\{1,2,3,4\}$, the score is $4$, which is the maximum.
题目信息
题号
agc076_e
时间限制
4 s
内存限制
1024 MB

题面与样例版权归 AtCoder 及出题人所有;中文翻译由 AI 生成(gpt-6.1-sol),如有出入请以原文为准。