Problem 1004-2017 ACM/ICPC Asia Regional Shenyang Online

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发布于 2019-02-21 17:09:54

5020

题目来源：array array array
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 0 Accepted Submission(s): 0
题目描述和输出： One day, Kaitou Kiddo had stolen a priceless diamond ring. But detective Conan blocked Kiddo’s path to escape from the museum. But Kiddo didn’t want to give it back. So, Kiddo asked Conan a question. If Conan could give a right answer, Kiddo would return the ring to the museum. Kiddo: “I have an array A and a number k, if you can choose exactly k elements from A and erase them, then the remaining array is in non-increasing order or non-decreasing order, we say A is a magic array. Now I want you to tell me whether A is a magic array. ” Conan: “emmmmm…” Now, Conan seems to be in trouble, can you help him?
Input The first line contains an integer T indicating the total number of test cases. Each test case starts with two integers n and k in one line, then one line with n integers: A1,A2…An. 1≤T≤20 1≤n≤10^5 0≤k≤n 1≤Ai≤10^5
Output For each test case, please output “A is a magic array.” if it is a magic array. Otherwise, output “A is not a magic array.” (without quotes).
Sample Input 3 4 1 1 4 3 7 5 2 4 1 3 1 2 6 1 1 4 3 5 4 6
Sample Output A is a magic array. A is a magic array. A is not a magic array.
题目分析：有T个测试样例，对于每个测试样例，给定两个整数，分别是数组元素个数n和需要删除的元素个数k,如果这个数组在删除了k个元素之后，是递增或者递减的，就称这个数组是magic array,否则不是。
做法：这道题是个经典的DP，换句话说就是模板题。
完整代码：

#include<iostream>
#include<algorithm>
#include<cstdio>
using namespace std;
#define MAX 100005
#define INF 100000000
int dp[MAX];
int a[MAX];
int k, T, n, flag;
int main()
{
    int temp;
    cin >> T;
    while (T-- > 0)
    {
        cin >> n >> k;
        memset(a, 0, sizeof(int)*MAX);
        for (int i = 0; i < n; i++)
            cin >> a[i];
        fill(dp, dp + n, INF);
        for (int i = 0; i < n; i++)
        {
            *upper_bound(dp, dp + n, a[i]) = a[i];
        }
        temp = 0;
        while (dp[temp]<INF)
        {
            temp++;
        }
        if (temp >= n - k)
            printf("A is a magic array.\n");
        else
            printf("A is not a magic array.\n");
    }
    return 0;
}

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原始发表：2017年09月10日，如有侵权请联系 cloudcommunity@tencent.com 删除

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