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문제

You want to transport $N$ artifacts through the Nile. The artifacts are numbered from $0$ to $N - 1$. The weight of artifact $i$ ($0 ≤ i < N$) is $W[i]$.

To transport the artifacts, you use specialized boats. Each boat can carry at most two artifacts.

  • If you decide to put a single artifact in a boat, the artifact weight can be arbitrary.
  • If you want to put two artifacts in the same boat, you have to make sure the boat is balanced evenly. Specifically, you can send artifacts $p$ and $q$ ($0 ≤ p < q < N$) in the same boat only if the absolute difference between their weights is at most $D$, that is $|W[p] - W[q]| ≤ D$.

To transport an artifact, you have to pay a cost that depends on the number of artifacts carried in the same boat. The cost of transporting artifact $i$ ($0 ≤ i < N$) is:

  • $A[i]$, if you put the artifact in its own boat, or
  • $B[i]$, if you put it in a boat together with some other artifact.

Note that in the latter case, you have to pay for both artifacts in the boat. Specifically, if you decide to send artifacts $p$ and $q$ ($0 ≤ p < q < N$) in the same boat, you need to pay $B[p] + B[q]$.

Sending an artifact in a boat by itself is always more expensive than sending it with some other artifact sharing the boat with it, so $B[i] < A[i]$ for all $i$ such that $0 ≤ i < N$.

Unfortunately, the river is very unpredictable and the value of $D$ changes often. Your task is to answer $Q$ questions numbered from $0$ to $Q - 1$. The questions are described by an array $E$ of length $Q$. The answer to question $j$ ($0 ≤ j < Q$) is the minimum total cost of transporting all $N$ artifacts, when the value of $D$ is equal to $E[j]$.

구현 상세

You should implement the following procedure.

std::vector<long long> calculate_costs(
    std::vector<int> W, std::vector<int> A,
    std::vector<int> B, std::vector<int> E)
  • $W$, $A$, $B$: arrays of integers of length $N$, describing the weights of the artifacts and the costs of transporting them.
  • $E$: an array of integers of length $Q$ describing the value of $D$ for each question.
  • This procedure should return an array $R$ of $Q$ integers containing the minimum total cost of transporting the artifacts, where $R[j]$ gives the cost when the value of $D$ is $E[j]$ (for each $j$ such that $0 ≤ j < Q$).
  • This procedure is called exactly once for each test case.

제한

  • $1 ≤ N ≤ 100\, 000$
  • $1 ≤ Q ≤ 100\, 000$
  • $1 ≤ W[i] ≤ 10^9$ for each $i$ such that $0 ≤ i < N$
  • $1 ≤ B[i] < A[i] ≤ 10^9$ for each $i$ such that $0 ≤ i < N$
  • $1 ≤ E[j] ≤ 10^9$ for each $j$ such that $0 ≤ j < Q$

서브태스크

번호배점제한
16

$Q ≤ 5$; $N ≤ 2000$; $W[i] = 1$ for each $i$ such that $0 ≤ i < N$

213

$Q ≤ 5$; $W[i] = i + 1$ for each $i$ such that $0 ≤ i < N$

317

$Q ≤ 5$; $A[i] = 2$ and $B[i] = 1$ for each $i$ such that $0 ≤ i < N$

411

$Q ≤ 5$; $N ≤ 2000$

520

$Q ≤ 5$

615

$A[i] = 2$ and $B[i] = 1$ for each $i$ such that $0 ≤ i < N$

718

No additional constraints.

예제

Consider the following call.

calculate_costs([15, 12, 2, 10, 21],
                [5, 4, 5, 6, 3],
                [1, 2, 2, 3, 2],
                [5, 9, 1])

In this example we have $N = 5$ artifacts and $Q = 3$ questions.

In the first question, $D = 5$. You can send artifacts $0$ and $3$ in one boat (since $|15 - 10| ≤ 5$) and the remaining artifacts in separate boats. This yields the minimum cost of transporting all the artifacts, which is $1 + 4 + 5 + 3 + 3 = 16$.

In the second question, $D = 9$. You can send artifacts $0$ and $1$ in one boat (since $|15 - 12| ≤ 9$) and send artifacts $2$ and $3$ in one boat (since $|2 - 10| ≤ 9$). The remaining artifact can be sent in a separate boat. This yields the minimum cost of transporting all the artifacts, which is $1 + 2 + 2 + 3 + 3 = 11$.

In the final question, $D = 1$. You need to send each artifact in its own boat. This yields the minimum cost of transporting all the artifacts, which is $5 + 4 + 5 + 6 + 3 = 23$.

Hence, this procedure should return $[16, 11, 23]$.

샘플 그레이더

Input format:

N
W[0] A[0] B[0]
W[1] A[1] B[1]
...
W[N-1] A[N-1] B[N-1]
Q
E[0]
E[1]
...
E[Q-1]

Output format:

R[0]
R[1]
...
R[S-1]

Here, $S$ is the length of the array $R$ returned by calculate_costs.

첨부

출처

Olympiad > International Olympiad in Informatics > IOI 2024 > Day 1 1번

  • 문제를 만든 사람: Pikatan Arya Bramajati

제출할 수 있는 언어

C++17, C++20, C++17 (Clang), C++20 (Clang)

채점 및 기타 정보

  • 예제는 채점하지 않는다.
  • 이 문제의 채점 우선 순위는 2이다.