Google KickStart 2019C CatchSome

Problem

传送门

Description

Bundle is an animal researcher and needs to go observe K dogs. She lives on a horizontal street marked at metre increments with consecutive numbers 0, 1, 2, 3 and so on. She begins in her home, which is at position 0. There are also N dogs on the street. The i-th dog is Pi metres to the right of her home on the street (multiple dogs can share the same position).

Dogs come in different colors, which are denoted by positive integers. The i-th animal is of color Ai.

If Bundle is at her home, she can change the current color of her shirt. This is important since the dogs are very shy! Bundle can only observe a dog if she is at the same position as that dog, and is wearing a shirt of the same color as the dog.

It takes Bundle one second to move one metre to the left or right on the street. It takes her no time to change shirts or observe a dog.

What is the least amount of time it will take Bundle to observe K dogs? Note that she does not have to return home after observing K dogs.

Input

The first line of the input gives the number of test cases, T. T test cases follow. Each testcase begins with a line containing the two integers N and K, the number of dogs on the number line and the number of dogs Bundle needs to observe, respectively. The second line contains N integers, the i-th of which is Pi, the position of the i-th dog. The third line contains N integers, the i-th of which is Ai, the color of the i-th dog.

Output

For each test case, output one line containing Case #x: y, where x is the test case number (starting from 1) and y is the least time Bundle needs to observe K dogs.

Limits

Time limit: 30 seconds per test set.
Memory limit: 1GB.
1 ≤ T ≤ 100.
1 ≤ KN.
1 ≤ Ai ≤ 1000.
1 ≤ Pi ≤ 105.

Test set 1 (Visible)

1 ≤ N ≤ 50.

Test set 2 (Hidden)

1 ≤ N ≤ 1000.

Sample

Input

1
2
3
4
5
6
7
8
9
10
3
4 3
1 2 4 9
3 3 2 3
4 3
1 2 3 4
1 8 1 8
6 6
4 3 3 1 3 10000
1 2 8 9 5 7

Output

1
2
3
Case #1: 8
Case #2: 6
Case #3: 10028

Hint

In Sample Case #1, there are N = 4 dogs and Bundle needs to observe K = 3 dogs. One way that she can achieve this is as follows:

  • Put on a shirt of color 3.
  • Move one metre to the right and observe the dog there.
  • Move one metre to the right again and observe the dog there.
  • Move two metres to the left, returning to her home.
  • Change into a shirt of color 2.
  • Move four metres to the right and observe the dog there.

In total, this takes Bundle 8 seconds which is the least time possible, so the answer is 8.

In Sample Case #2, there are N = 4 dogs and Bundle needs to observe K = 3 dogs. One way that she can achieve this is as follows:

  • Put on a shirt of color 1.
  • Move one metre to the right and observe the dog there.
  • Move one metre to the left, returning to her home.
  • Change into a shirt of color 2.
  • Move two metres to the right and observe the dog there.
  • Move two metres to the right again and observe the dog there. Note that Bundle is unable to observe the dog she passes at position 3, since her shirt is the wrong color (even though she was wearing the right colored shirt previously).

In total, this takes Bundle 6 seconds which is the least time possible, so the answer is 6.

In Sample Case #3, note that:

  • Multiple dogs can share the same position and
  • Dogs are not necessarily given in ascending order of position.

No explanation is provided for the answer to this case.

Solution

Idea

可以发现颜色的大小远远大于狗的数量,所以可以对颜色离散化。离散化后建立一个二维数组G[i] [j], 表示第i种颜色中第j只狗所在的位置。

然后使用dp。ldp[i] [j]表示前i种颜色中照看j只狗所要的时间(这里dp记录的都是要回家的,故时间要*2), rdp[i] [j] 表示从第i种颜色开始直到最后一种颜色的狗中照看j只狗所要的时间。

所以我们要求的时间为 : ans = ldp[i] [k] + G[i] [j-1] + rdp[i+1] [K-k-j], 选一个最小值。(详看代码)

Code

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#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
const int inf = 1012345678;
int main() {
cin.tie(0);
ios_base::sync_with_stdio(false);
int Q;
cin >> Q;
for (int rep = 1; rep <= Q; ++rep) {
int N, K;
cin >> N >> K;
vector<int> P(N), A(N);
for (int i = 0; i < N; ++i) cin >> P[i];
for (int i = 0; i < N; ++i) cin >> A[i];
vector<int> comp = A;
sort(comp.begin(), comp.end());
comp.erase(unique(comp.begin(), comp.end()), comp.end());
for (int i = 0; i < N; ++i) {
A[i] = lower_bound(comp.begin(), comp.end(), A[i]) - comp.begin();
}
int M = comp.size();
vector<vector<int> > G(M);
for (int i = 0; i < N; ++i) {
G[A[i]].push_back(P[i]);
}
for (int i = 0; i < M; ++i) {
sort(G[i].begin(), G[i].end());
}
vector<vector<int> > ldp(M + 1, vector<int>(K + 1, inf)), rdp(M + 1, vector<int>(K + 1, inf));
ldp[0][0] = 0; rdp[M][0] = 0;
for (int i = 0; i < M; ++i) {
ldp[i + 1] = ldp[i];
for (int j = 1; j <= G[i].size(); ++j) {
for (int k = j; k <= K; ++k) {
ldp[i + 1][k] = min(ldp[i + 1][k], ldp[i][k - j] + G[i][j - 1] * 2);
}
}
for (int j = K - 1; j >= 0; --j) {
ldp[i + 1][j] = min(ldp[i + 1][j], ldp[i + 1][j + 1]);
}
}
for (int i = M - 1; i >= 0; --i) {
rdp[i] = rdp[i + 1];
for (int j = 1; j <= G[i].size(); ++j) {
for (int k = j; k <= K; ++k) {
rdp[i][k] = min(rdp[i][k], rdp[i + 1][k - j] + G[i][j - 1] * 2);
}
}
for (int j = K - 1; j >= 0; --j) {
rdp[i][j] = min(rdp[i][j], rdp[i][j + 1]);
}
}
int ans = inf;
for (int i = 0; i < M; ++i) {
for (int j = 1; j <= G[i].size() && j <= K; ++j) {
for (int k = 0; k <= K - j; ++k) {
ans = min(ans, ldp[i][k] + rdp[i + 1][K - j - k] + G[i][j - 1]);
}
}
}
cout << "Case #" << rep << ": " << ans << endl;
}
return 0;
}
❤采之欲遗谁,所思在远道。❤
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